Prognostic biomarkers for TTK inhibitor chemotherapy

ABSTRACT

A method for identifying a tumor that is susceptible to treatment with a TTK inhibitor, including: a) providing a sample of a tumor; b) determining the presence of a mutated CTNNB1 gene in the sample, wherein the mutation is located in exon 3 of CTNNB1 and the presence of a mutated CTNNB1 gene indicates the tumor is susceptible to treatment with a TTK inhibitor. Alternatively, step b) is replaced by the step of determining the presence of a mutated CTNNB1 protein in the sample, wherein the mutation is located in exon 3 of CTNNB1 and the presence of a mutated CTNNB1 protein indicates the tumor is susceptible to treatment with a TTK inhibitor. In a further alternative, step b) includes determining an altered expression of a CTNNB1 regulated gene, whereby an altered expression of a CTNNB1 regulated gene indicates the tumor is susceptible to treatment with a TTK inhibitor.

FIELD OF THE INVENTION

The present invention relates to methods to detect the mutant status of the CTNNB1 gene or CTNNB1 protein or the altered expression of a CTNNB1 regulated gene to identify tumors that are susceptible to anticancer therapy with a TTK inhibitor. The present invention also relates to methods to predict the outcome, or disease progression, of cancers that are treated with a TTK inhibitor, by detection of the mutant status of the CTNNB1 gene or CTNNB1 protein or the altered expression of a CTNNB1 regulated gene

BACKGROUND OF THE INVENTION

Targeted therapies bring great benefit to cancer patients because they can improve survival rates with fewer side effects than traditional, less selective cytotoxic drugs. Small molecule inhibitors of protein kinases are a prime example of the success of targeted therapy: many of these inhibitors exploit unique features of tumor cells, permitting cancer specificity while having limited effects on healthy cells. A classic example of a targeted therapy is the use of tyrosine kinase inhibitors and antibodies in breast cancer patients with amplification or overexpression of the HER2 gene (Higgins, M. J., and Baselga, J., J. Clin. Invest. 121: 3797; 2011).

To determine whether it is likely that a patient will respond to a certain targeted therapy, it is important to determine the status and presence of biomarkers that correlate with drug sensitivity in specimens of the patient's tumor, before the start of treatment.

The protein kinase TTK (EC 2.7.12.1), commonly referred to as Mps1, is a component of the spindle assembly checkpoint (SAC), a surveillance mechanism that ensures the fidelity of chromosome segregation (Liu, X., and Winey, M., Annu. Rev. Biochem. 81: 561; 2012). Defects in SAC functioning can lead to chromosome segregation errors by allowing mitotic exit in the presence of unattached kinetochores. Complete loss of SAC function is lethal in mice (Baker, D. J., et al., Curr. Opin. Cell Biol. 17, 583; 2005) and incompatible with the viability of human cell lines (Michel, L., et al. Proc. Natl. Acad. Sci. USA 101, 4459; 2004; Kops G. J., et al. Proc. Natl. Acad. Sci. USA 101, 8699; 2004). TTK mRNA levels are elevated in various human cancers, including breast, thyroid papillary carcinoma, hepatocellular carcinoma, pancreatic ductal adenocarcinoma, glioma, gastric, bronchogenic, and lung (Daniel, J., et al. Proc. Natl. Acad. Sci. USA 108: 5384; 2011; Maire, V., et al., PLoS ONE 8(5) e63712; 2013; Kilpinen, S., et al., PLoS ONE 5(12), e15068; 2010; Landi, M. T., et al., PLoS ONE 3(2) e1651; 2008; Liang, X. D., et al. PLoS ONE 9(6), e97739; 2014; Mills, G. B., et al. J. Biol. Chem. 267: 16000; 1992; Mir, S. E., et al., Cancer Cell 18: 244; 2010; Salvatore, G., et al., Cancer Res. 67: 10148; 2007: Slee, R. B., et al., Mol. Cancer Ther. 13: 307; 2014; Tannous, B. A., et al., J. Natl. Cancer Inst. 105: 1322; 2013; Yuan, B., et al., Clin. Cancer Res. 12: 405; 2006). Therefore, chemical compounds that inhibit the activity of TTK are useful in the treatment of a variety of cancers. These compounds may be applied as single agents, or in combination with other anti-cancer agents.

Different compounds have been disclosed which show an inhibitory effect on TTK. AstraZeneca UK Ltd. disclosed 2-anilinopurin-8-ones as inhibitors of TTK in WO2009/024824 A1. In WO2011/013729 A1, fused imidazoles, and in WO2011/016472 A1 pyridine and pyrimidine derivatives are disclosed as inhibitors of TTK by Oncotherapy Science Inc. Indazoles for inhibition of TTK have been disclosed by University Health Network in WO2011/123937 A1, WO2013/053051 A1 and WO2014/056083 A1. Dana Farber Cancer Institute disclosed pyrimido-diazepinones as inhibitors of TTK in WO2010/080712 A1. In WO2009/156315 A1, pyrazolo-quinazolines, in WO2012/101029 A1 tricyclic derivatives, in WO2010/108921 A1, N-aryl-2-(2-arylaminopyrimidin-4-yl)pyrrol-4-carboxamides, in WO2012/013557 A1, isoxazolo-quinazolines, in WO2012/101032 A1, tricyclic pyrrolo derivatives and in WO2012/139930 A1, pyrazolyl-pyrimidines are disclosed as inhibitors of TTK by Nerviano Medical Sciences S.R.L.

Myriad Pharmaceuticals Inc. disclosed purines as inhibitors of TTK in WO2010/111406 A2. Furthermore, Cancer Research Technology Ltd. disclosed pyrrolopyridineamino derivatives in WO2012/123745 A1 and bicycles in WO2014/037750 A1 and in WO2014/037751 A1 as inhibitors of TTK.

In WO2010/124826 A1, imidazoquinoxalines, in WO2011/026579 A1, aminoquinoxalines, in WO2011/063907 A1, WO2011/063908 A1, WO2011/064328 A1, WO2011/157688 A1, WO2012/143329 A1, WO2014/009219 A1, WO2014/195274 A1, WO2014/195276 A1 and WO2014/198647 A1, triazolopyridines, in WO2012/136531 A1, imidazopyridines, in WO2012/130905 A1, substituted benzimidazoles, in WO2012/032031 A1, WO2013/135612 A1 and WO2014/131739 A1, imidazopyridazines, in WO2011/113862 A1, WO2011/151259 A1, WO2012/080228 A1, WO2012/080229 A1, WO2012/080230 A1, WO2012/080232 A1, WO2012/080234 A1 and WO 2012/080236 A1, imidazopyrazines are respectively disclosed as inhibitors of TTK by Bayer Schering Pharma A.G.

Representative compounds of the different chemical classes have been investigated in cell proliferation assays with different human cancer cell lines. A representative TTK inhibitor of the imidazo-pyrazines, Mps-BAY2b, was shown to inhibit the proliferation of twenty-seven human cancer cell lines from different tumor origins with an IC₅₀ of 160 nM to 4.3 μM (Jemaa, M., et al., Cell Death Different. 20: 1532; 2013); no correlation was found between the response and the pattern of genomic instability, the activity of several proteins relevant for oncogenesis, or the functionality of the SAC.

NMS-P715, a representative of the pyrazolo-quinazoline class, inhibited the proliferation of a wide range of cell lines in a panel of 127 cancer cell lines (Colombo, R., et al., Cancer Res. 70: 10255; 2010); IC₅₀s were close to 1 μM or higher and there was no correlation observed between anti-proliferative effects and cellular doubling time.

MPI-04079605, a TTK inhibitor disclosed by Myriad, was shown to inhibit the growth of fourteen human cancer cell lines from different tumor origins, but only after prolonged incubation time (Tardif, K. D., et al., Mol. Cancer Res. 10: 2267; 2011).

CCT251455, a representative of the 1H-pyrrolo[2,3-c]pyridine class, inhibited the proliferation of HCT116 cells with a GI₅₀ of 160 nM (Naud, S., et al., J. Med. Chem. 56: 10045; 2013).

An imidazo[1,2-b]pyridazine-based TTK inhibitor disclosed by Shionogi, was shown to inhibit the proliferation of fourteen human cancer cell lines from different tumor origins with an IC₅₀ of 3.3 nM to 320 nM (Kusakabe, K., et al., J. Med. Chem. 58: 1716; 2015); CFI-401870, a representative of the indazoles, inhibited the proliferation of a wide range of cell lines in a panel of 22 cancer cell lines (Liu, Y., et al., J. Med. Chem. 58: ASAP; 2015) with GI₅₀s of 8 nM to 70 nM.

Whereas in the above cited profiling experiments, different cancer cell lines showed different relative sensitivities for TTK inhibitors, no genomic or other markers were identified that correlated with sensitivity to TTK inhibitors.

Several TTK inhibitors of the above mentioned chemical classes have been shown to reduce growth of xenografts in mouse models of melanoma (Colombo, R., et al.), colorectal carcinoma (Jemaa, M., et al.; Tardif, et al.; Laufer, R., et al., Bioorg. Med. Chem. 22: 4968; 2014), cervical carcinoma (Jemaa, M., et al.) and glioblastoma cells (Tannous, B. A. et al.), demonstrating the potential use of TTK inhibitors in treatment of various cancers.

In view of the broad activity of TTK inhibitors in many different cell lines and tumor types, there is a clear need for biomarkers that can be used to predict which cancers are most likely to respond to chemotherapeutic treatment with a TTK inhibitor. Such a prognostic drug sensitivity biomarker can be used to identify the most optimal patient population to the application of drug therapy with a TTK inhibitor, or can be used to predict the progression, or outcome of disease treated with a TTK inhibitor.

Statement of the Invention

In accordance with a first aspect of the present invention there is provided a method as defined in claim 1 appended hereto.

The present inventors have surprisingly observed that cancer cells that harbor mutations in the CTNNB1 gene (HUGO name: CTNNB1) are more sensitive to TTK inhibitors than normal cells or cancer cells that do not express mutant CTNNB1 (CTNNB1 proficient cells).

The CTNNB1 gene encodes a dual function protein, β-catenin, which regulates the coordination of cell adhesion and regulates gene transcription in the Wnt signaling pathway (Logan, C. Y., and Nusse, R., Annu. Rev. Cell. Dev. Biol. 896: 1998; 2004). Mutations in the CTNNB1 gene have been found in many cancers, including colorectal (Morin, P. J. et al., Science 275: 1787; 1997; Iwao, K., et al., Cancer Res. 58: 1021; 1998; Sparks, A. B., et al. Cancer Res. 58: 1130; 1998), and hepatocellular carcinoma (Miyoshi, Y., et al., Cancer Res. 58: 2524; 1998; Chen, Y. W., et al., Hepatology 36: 927; 2002), melanoma (Rubinfeld, B., et al., Science 275: 1790; 1997), medulloblastoma (Zurrawel, R. H., et al. Cancer Res. 58: 896; 1998), lung (Shigemitsu, K., et al., Oncogene 20: 4249; 2001), endometrial (Fukuchi, T., et al., Cancer Res. 58: 3526; 1998; Liu, Y., et al., J. Natl. Canc. Inst. 106(9); 2014), ovarium (Palacios, J., and Gamallo, C., Cancer Res. 58: 1344; 1998) and prostate cancer (Voeller, H. J., and Gelmann, E. P., Cancer Res. 58, 2520; 1998).

The activity of β-catenin is regulated by phosphorylation at serine and threonine residues by the protein kinases glycogen synthase kinase 33 (JGSK31) and casein kinase I (CKI), followed by ubiquitination and degradation by the proteasome (Liu, C., et al. Cell 108, 837; 2002). Mutations in the CTNNB1 gene resulting in deletion or substitution of one or more of these serine or threonine residues impairs phosphorylation and degradation, resulting in an overactive β-catenin, and uncontrolled cell growth (Morin, P. J. et al., Science 275: 1787; 1997; Liu, C., et al.).

The present invention provides methods to determine the mutant status of CTNNB1 in tumor derived materials, to determine the susceptibility of said tumors to anticancer therapy with a TTK inhibitor. The present invention also provides methods to determine the mutant status of CTNNB1 to monitor the effectiveness of therapy of proliferative disease with a TTK inhibitor, or to predict the outcome of cancers that are treated with a TTK inhibitor.

The analysis of the mutant status of CTNNB1 may be performed in combination with analyses of the mutant status or expression of other genes and/or proteins, or may be confined to an analysis of only CTNNB1 gene status.

The present invention constitutes a diagnostic method. However, the method is not performed directly on the human or animal body. The diagnostic method may be performed in a laboratory, but provides results that allow a physician to make an accurate prognosis of disease progression in a cancer patient, particularly with respect to whether a patient is likely to respond to chemotherapy with a TTK inhibitor, applied either as a single agent, or in combination with other therapeutic agents or radiotherapy.

More specifically, the present invention provides methods to determine the status of oncogenic CTNNB1 mutations in tumor derived materials to determine the susceptibility of said tumors in anti-cancer therapy with a TTK inhibitor as defined in Formulas I-VIII detailed herein.

Many different mutations in β-catenin have been observed in cancer patients, and these have been categorized in databases such as COSMIC (http://cancer.sanger.ac.uk/cancergenome/projects/cosmic/). The expression of CTNNB1 mutations in human cancers is reported in The Cancer Genome Atlas, which can be accessed at http://www.cancerenome.nih.gov.

A link to the CTNNB1 nucleic acid and protein sequence can be found at http://www.genenames.org/cgi-bin/ene_symbol_report?hgnc_id=2514 the disclosure of which is herein incorporated by reference. The protein sequence and amino acid numbering of CTNNB1 is also given in FIG. 1 appended hereto.

Exon 3 of CTNNB1 contains a hot spot of mutations that affect the ability of kinases to phosphorylate β-catenin (Morin, P. J. et al., 1997). The lack of this phosphorylation results in β-catenin accumulation in the nucleus (Liu, C. et al., 2002). More specifically, mutation or deletion of the serine residues at positions 33, 37 or 45, or mutation or deletion of the threonine residue at position 41 alter the GSK3β phosphorylation motifs which participate in the degradation of β-catenin (Rubinfeld, B., et al.; Morin, P. J., et al.). Consequently, these mutations result in increased oncogenic signaling (Rubinfeld, B., et al.; Morin, P. J., et al.).

In accordance with a further aspect of the invention there is provided a method according to claims 15 to 18 appended hereto. Specifically, a method is described to determine whether a chemical compound is a TTK inhibitor, said method comprising the steps of: a) Providing first and second mammalian cell lines, wherein the first cell line is CTNNB1-mutated and the second cell line is CTNNB1 proficient; b) Contacting said first and second cell lines with a first candidate compound; and, c) Determining by assay the inhibition of cell proliferation of said first and second cell lines. In an important variant of this method, steps b) and c) as mentioned above are repeated with a second candidate compound and a selection of candidate compound is made based on the activity of the respective candidate compounds in the assay with said first cell line.

In an embodiment, the first and second cell lines used in this method may be cancer cell lines. In an alternative embodiment, the first and second cell lines may be isogenic cell lines.

The present inventors have surprisingly observed that expression of three of the mutations described above correlates with increased susceptibility of cancer cells to chemical inhibitors of TTK. Therefore, detection of the mutant status of the CTNNB1 gene at serine 33, threonine 41, or serine 45 can be used to determine the susceptibility of tumors for treatment with TTK inhibitors.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be described with reference to the appended figures in which:

FIG. 1 is the protein sequence and amino acid numbering of CTNNB1 (β-catenin) (UniProt code P35222) (SEQ ID NO: 1). Mutation or deletion of the underlined serine (S) or threonine (T) residues at positions 33, 37, 41 and 45 alter the phosphorylation and degradation of β-catenin (Rubinfeld, B., et al.; Morin, P. J., et al.).

FIGS. 2A-2G represent the volcano plots of cellular profiling in 66 cancer cell lines for Examples 5, 8, 9, 12, 13, 17 and 20.

For completeness, a volcano plot is a graphical representation of an analysis of variance (Anova) of the association of cancer gene mutations present in cell lines and the response of these cell lines in proliferation assays with compounds. The volcano plot shows the average IC₅₀ shift between mutant and non-mutant cell lines (x-axis) and the significance from the Anova test (y-axis). Significance was corrected for multiple-testing and all associations above the threshold level (dotted line) are filled in black. Areas of circles are proportional with the number of cell lines carrying mutations. The cancer cell lines used in the drug sensitivity analysis are listed in Table 1 herein below.

DETAILED DESCRIPTION OF THE INVENTION

Methods of obtaining a sample of a tumor for analysis are well known in the art and require no specific elucidation here. The mutant status of the CTNNB1 gene of a tumor from an individual with cancer can be determined by analyzing the DNA sequence of a sample of the tumor, and comparing the tumor DNA sequence with that in healthy tissue, or with the ‘wild-type’ CTNNB1 sequence, referred to in the UniProt data base as P35222, and displayed in FIG. 1. A DNA sample may be taken directly from a tumor biopsy, or may be derived from circulating tumor DNA (Diaz, L. A., et al., Nature 486: 537; 2012). The mutant status of the CTNNB1 gene may also be determined by sequencing of the mRNA of the tumor sample, or may be determined indirectly by analysis of the amino acid sequence of β-catenin, or by determination of the phosphorylation status of β-catenin using specific antibodies.

As the mutations affect the degradation of β-catenin, they affect the total cellular levels of 3-catenin and the amount β-catenin in the nucleus. Therefore, the mutant status of the CTNNB1 gene may also be determined indirectly by determining total or nuclear β-catenin levels in tumor cells.

Alternatively, the mutant status of CTNNB1 may be determined by analyzing the expression of genes that are regulated by β-catenin. The detection of β-catenin-regulated genes may be determined by extracting RNA from a sample of a tumor and measuring gene expression using reverse-transcriptase polymerase chain reaction (RT-PCR) or using microarray analysis. Many genes regulated by β-catenin have been described, and include Axin2 (Yan, D. et al., Proc. Natl. Acad. Sci. USA 98: 14973; 2001), c-myc (He, T. C. et al., Science 281: 1509; 1998) and LGR5 (Barker, N. et al., Nature 499: 1003; 2007). A comprehensive list of β-catenin-regulated genes can be found at the Wnt home page (http://web.stanford.edu/group/nusselab/cgi-bin/wnt/targetgenes) and in scientific articles (Willert, J. et al., BMC Dev. Biol. 2:8; van de Wetering, M et al., Cell 111: 241; 2002).

The expression of β-catenin-regulated genes may also be determined at the protein level, using specific antibodies or mass-spectroscopy-based methods. Since several β-catenin-regulated genes are oncogenes, the mutant status of CTNNB1 can also be determined by measuring oncogenic signaling.

Examples of inhibitors of TTK are chemical compounds belonging to the class of (5,6-dihydro)pyrimido[4,5-e]indolizines according to Formula I or pharmaceutically acceptable salts thereof.

wherein,

-   R¹ is selected from the group consisting of:

-   R¹¹ is H, halogen, (1-2C)alkyl, (2-3C)alkenyl, (2-3C)alkynyl,     (1-2C)alkoxy or OC₂H₃, all alkyl and alkoxy groups optionally being     substituted with one or more halogen; -   R¹² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; -   R¹³ is R¹³¹CH₂, R¹³²O, R¹³³R¹³⁴N, R¹³⁵C(O), R¹³⁶S, R¹³⁶S(O),     R¹³⁶S(O)(NH), R¹³⁷SO₂, (2-7C)heterocycloalkyl, or (1-5C)heteroaryl     each heterocycloalkyl or heteroaryl optionally being substituted     with (1-2C)alkyl, fluoro, hydroxyl, oxo, (1-2C)alkoxy,     (1-6C)alkylcarbonyl, (1-6C)alkylsulfonyl, (1-5C)alkoxycarbonyl,     (1-6C)alkylaminocarbonyl, (3-6C)cycloalkylcarbonyl,     (2-7C)heterocycloalkylcarbonyl or di[(1-2C)alkyl]amino, each     alkylcarbonyl, alkylsulfonyl, alkoxycarbonyl, alkylaminocarbonyl,     cycloalkylcarbonyl or heterocycloalkylcarbonyl optionally being     substituted with (1-2C)alkyl, fluoro, hydroxyl, cyano, oxo or     (1-2C)alkoxy; -   R¹³¹ is (1-6C)alkylcarbonylamino, (3-6C)cycloalkylcarbonylamino or     (2-7C)heterocycloalkylcarbonylamino each optionally substituted with     one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or     (1-2C)alkoxy; -   R¹³² is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl,     (6-10C)aryl or (1-5C)heteroraryl each optionally substituted with     one or more groups selected from (1-2C)alkyl, halogen, hydroxyl,     (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; -   R¹³³ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl     (1-6C)alkylcarbonyl, (1-5C)alkoxycarbonyl, (3-6C)cycloalkylcarbonyl     or (2-7C)heterocycloalkylcarbonyl, each optionally substituted with     one or more groups selected from (1-2C)alkyl, halogen, hydroxyl or     (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; -   R¹³⁴ is hydrogen or (1-2C)alkyl; -   R¹³⁵ is (2-7C)heterocycloalkyl, (1-6C)alkylamino,     di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino or     (3-6C)cycloalkylamino each optionally substituted with one or more     groups selected from (1-2C)alkyl, fluoro, hydroxyl, (1-2C)alkoxy,     di[(1-2C)alkyl]amino, (2-7C)heterocycloalkyl, oxo, cyano or amino; -   R¹³⁶ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl each     optionally substituted with one or more groups selected from     (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; -   R¹³⁷ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl,     (1-6C)alkylamino, di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino     or (3-6C)cycloalkylamino, each optionally substituted with one or     more groups selected from (1-2C)alkyl, fluoro, hydroxyl or     (1-2C)alkoxy; -   R¹⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; and -   R^(is) is H, halogen.

In the above Formula I, R² is selected from the group consisting of:

-   R²¹ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl,     (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; -   R²² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; -   R²³ is H, halogen, (1-2C)alkyl, (1-2C)alkoxy, cyano or hydroxy; -   R²⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; -   R²⁵ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl,     (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; -   R²⁶ is H, (1-6C)alkyl, (3-6C)cycloalkyl, (2-5C)heterocycloalkyl,     (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl, wherein n represents an     integer of 1, 2, 3 or 4, all alkyl, heterocycloalkyl and     (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl groups optionally     substituted with one or more groups selected from (1-2C)alkyl,     (1-2C)alkoxy, hydroxyl, oxo, amino, (3-6C)cycloalkyl,     di[(1-2C)alkyl]amino or (2-5C)heterocycloalkyl.

In the above Formula I only one of R²¹ and R²⁵ in R² can be H.

Other examples of known TTK inhibitors are chemical compounds belonging to the class of pyrazolo-quinazolines according to Formula II or pharmaceutically acceptable salts thereof as described in WO2009/156315 A1.

wherein,

-   -   R¹ and R³ are independently selected from the group consisting         of (6-10C)aryl and (1-5C)heteroaryl, wherein both groups         optionally can be substituted;     -   R² is selected from the group consisting of (1-6C)alkyl and         (2-6C)alkenyl, wherein both groups optionally can be         substituted;     -   R⁴ is selected from the group consisting of hydrogen and         (1-6C)alkyl, wherein both groups optionally can be substituted;     -   R⁵ and R⁶ are independently hydrogen or methyl.

Other, known TTK inhibitors are chemical compounds belonging to the class of imidazo-pyrazines according to Formula III or pharmaceutically acceptable salts thereof as described in WO2011/013729 A1, WO2011/113862 A1, WO2011/151259 A1, WO2012/080228 A1, WO2012/080229 A1, WO2012/080230 A1, WO2012/080232 A1, WO2012/080234 A1 and WO 2012/080236 A1.

wherein,

-   -   R¹ is selected from the group consisting of (1-6C)alkyl,         halo(1-6C)alkyl, HO-(1-6C)alkyl, H₂N-(1-6C)alkyl,         cyano(1-6C)alkyl, (1-6C)alkoxy(1-6C)alkyl, (2-6C)alkenyl,         (2-6C)alkynyl, (3-6C)cycloalkyl, (3-7C)heterocycloalkyl,         (6-10C)aryl and (1-5C)heteroaryl, wherein said groups optionally         can be substituted;     -   R² is selected from the group consisting of (6-10C)aryl and         (1-9C)heteroaryl, wherein both groups optionally can be         substituted;     -   R³ is selected from the group consisting of: (1-6C)alkyl,         —(CH₂)_(n)-(3-7C) heterocycloalkyl),         —(CH₂)_(n)-(4-8C)heterocycloalkenyl), (3-7C)heterocycloalkyl,         (6-10C)aryl, (1-9C)heteroaryl, —(CH₂)_(n)-(6-10C)aryl,         —O-(6-10C)aryl, —C(═O)N and cyano, wherein said groups can be         substituted and further wherein n is an integer of 0, 1 or 2.

Another example of known TTK inhibitors are chemical compounds belonging to the class of purines according to Formula IV or pharmaceutically acceptable salts thereof as described in WO2010/111406 A1.

wherein,

-   -   R¹ is selected from the group consisting of (3-6C)cycloalkyl and         (3-7C)heterocycloalkyl, wherein said groups optionally can be         substituted; and,     -   R² is selected from the group consisting of:         -   a) (6-10C)aryl, and,         -   b) (1-5C)heteroaryl,     -   wherein both groups optionally can be substituted.

Yet, other known TTK inhibitors are chemical compounds belonging to the class of imidazopyridazines according to Formula V or pharmaceutically acceptable salts thereof as described in WO2011/013729 A1, WO2012/032031 A1, WO2013/135612 A1 and WO2014/131739 A1.

wherein,

-   -   R¹ is selected from the group consisting of hydrogen,         (1-6C)alkyl, halo(1-6C)alkyl, HO(1-6C)alkyl, (3-6C)cycloalkyl,         (3-7C)heterocycloalkyl and (1-5C)heteroaryl, wherein said groups         optionally can be substituted;     -   R² is (6-10C)aryl or (1-9C)heteroaryl, each of which may be         optionally substituted;     -   R³ is selected from the group consisting of X-(6-10C)aryl or         X-(1-9C)heteroaryl, wherein both groups optionally can be         substituted, wherein X represents S(═O)_(p), O, NR⁴,         CR^(4a)R^(4b), C═CR^(4a)R^(4b) and further wherein p is an         integer of 0, 1, 2;     -   R⁴, R^(4a), R^(4b) represent independently from each other a         hydrogen atom or (1-6C)alkyl.

Other, known TTK inhibitors are chemical compounds belonging to the class of triazolopyridines according to Formula VI or pharmaceutically acceptable salts thereof as described in WO2011/063907 A1, WO2011/063908 A1, WO2011/064328 A1, WO2011/157688 A1, WO2012/143329 A1, WO2014/009219 A1, WO2014/195274 A1, WO2014/195276 and WO2014/198647 A1.

wherein,

-   -   R¹ represents a phenyl group, a pyridyl group or an indolyl         group wherein said groups can optionally be substituted;     -   R² represents a phenyl group, a pyridyl group or a pyrimidyl         group wherein said groups can optionally substituted;     -   R³ represents a group selected from: hydrogen or         —C(═O)—O—(CR⁷R⁸)—O—C(═O)—R⁴ wherein R⁴ represents a group         selected from: (1-6C)alkyl, substituted one or more times,         identically or differentially, with a group selected from: —NH₂,         —N(H)R⁵, —N(R⁵)R⁶, (4-7C)heterocycloalkyl, optionally         substituted, one or more times, identically or differentially,         with a group selected from —NH₂, —N(H)R⁵, —N(R⁵)R⁶.     -   R⁵ and R⁶, independently from each other, represent a group         selected from a hydrogen atom and (1-3C)alkyl.     -   R⁷ represents a group selected from a hydrogen atom and         (1-3C)alkyl.     -   R⁸ represents a hydrogen atom

Another example of known TTK inhibitors are chemical compounds belonging to the class of pyrrolopyridines according to Formula VII or pharmaceutically acceptable salts thereof as described in WO2009/032694 A1, WO2009/032703 A1 and Nature Chemical Biology 6 (2010), 359.

wherein,

-   -   R¹ is selected from the group consisting of (6-10C)aryl, wherein         said group optionally can be substituted;     -   R² is selected from the group consisting of (6-10C)aryl, wherein         said group optionally can be substituted.

Yet, another example of known TTK inhibitors are chemical compounds belonging to the class of aminoyridines and aminopyrimidines according to Formula VIII or pharmaceutically acceptable salts thereof as described in WO2011/016472 A1, ACS Med. Chem. Letters 3 (2012), 560 and Bioorg. Med. Chem. Letters 23 (2015), 2247.

wherein,

-   -   R¹ is selected from the group consisting of hydrogen atom or         amino;     -   R² is selected from the group consisting of (6-10C)aryl,         (1-5C)heteroaryl, (1-6C)alkyl, (3-6C)cycloalkyl and         (3-7C)heterocycloalkyl, wherein said groups optionally can be         substituted;     -   R³ is selected from the group consisting of (6-10C)aryl, wherein         said groups optionally can be substituted;     -   X is C or N.

The terms as used herein refer to the following:

Halogen means fluorine, chlorine, bromine or iodine.

-   (1-2C)Alkyl means an alkyl group having 1 to 2 carbon atoms, being     methyl or ethyl. A methyl group may be indicated as Me or CH₃. -   (1-3C)Alkyl means a branched or unbranched alkyl group having 1-3     carbon atoms, being methyl, ethyl, propyl or isopropyl. -   (1-4C)Alkyl means a branched or unbranched alkyl group having 1-4     carbon atoms, being methyl, ethyl, propyl, isopropyl, butyl,     isobutyl, sec-butyl or tert-butyl, (1-3C)alkyl groups being     preferred. -   (1-5C)Alkyl means a branched or unbranched alkyl group having 1-5     carbon atoms, for example methyl, ethyl, propyl, isopropyl, butyl,     isobutyl, sec-butyl, tert-butyl, pentyl and isopentyl, (1-4C)alkyl     groups being preferred. -   (1-6C)Alkyl means a branched or unbranched alkyl group having 1-6     carbon atoms, for example methyl, ethyl, propyl, isopropyl, butyl,     tert-butyl, n-pentyl and n-hexyl. (1-5C)alkyl groups are preferred,     (1-4C)alkyl being more preferred. -   (1-2C)Alkoxy means an alkoxy group having 1-2 carbon atoms, the     alkyl moiety having the same meaning as previously defined. -   (2-4C)Alkoxy means an alkoxy group having 2-4 carbon atoms, for     example ethoxy, propyloxy, butyloxy, isopropyloxy, isobutyloxy, and     tertbutyloxy. Ethyloxy and propyloxy being preferred. Ethyloxy     groups being more preferred. -   (1-3C)Alkoxy means an alkoxy group having 1-3 carbon atoms, the     alkyl moiety having the same meaning as previously defined.     (1-2C)Alkoxy groups are preferred. -   (1-4C)Alkoxy means an alkoxy group having 1-4 carbon atoms, the     alkyl moiety having the same meaning as previously defined.     (1-3C)alkoxy groups are preferred, (1-2C)alkoxy groups being most     preferred. -   (1-5C)Alkoxy means an alkoxy group having 1-5 carbon atoms, the     alkyl moiety having the same meaning as previously defined.     (1-4C)Alkoxy groups are preferred, (1-3C)alkoxy groups being more     preferred. -   (2-3C)Alkenyl means a branched or unbranched alkenyl group having     2-3 carbon atoms, such as ethenyl or 2-propenyl. -   (2-3C)Alkynyl means ethynyl or 2-propynyl. -   (3-4C)Cycloalkyl means a cycloalkyl group having 3-4 carbon atoms,     being cyclopropyl or cyclobutyl. -   (3-6C)cycloalkyl means a cycloalkyl group having 3-6 atoms. Examples     of “cycloalkyl” include, but are not limited to, cyclopropyl,     cyclobutyl, cyclopentyl or cyclohexyl. -   (2-5C)Heterocycloalkyl means a heterocycloalkyl group having 2-5     carbon atoms, preferably 3-5 carbon atoms; and one or two     heteroatoms selected from N, O and/or S, which may be attached via a     heteroatom if feasible, or a carbon atom. Preferred heteroatoms are     N or O. Preferred are oxetanyl, azetidinyl, piperidinyl,     morpholinyl, pyrrolidinyl and piperazinyl. Most preferred     (2-5C)heterocycloalkyl are oxetanyl and azetidinyl. -   (2-7C)Heterocycloalkyl means a heterocycloalkyl group having 2-7     carbon atoms, preferably 2-5 carbon atoms, and one or two     heteroatoms selected from N, O and/or S. Preferred heteroatoms are N     or O. Preferred (2-7C)heterocycloalkyl groups are azetidinyl,     pyrrolidinyl, piperidinyl, piperazinyl, homopiperidinyl, morpholinyl     or thiomorpholinyl. The heterocycloalkyl group may be attached via a     heteroatom if feasible. -   (6-10C)Aryl means an aromatic hydrocarbon group having 6-10 carbon     atoms. Examples of “(6-10C)aryl” include, but are not limited to,     phenyl, naphthyl, tetrahydronaphthyl or indenyl. -   (1-5C)Heteroaryl means a substituted or unsubstituted aromatic group     having 1-5 carbon atoms and 1-4 heteroatoms selected from N, O     and/or S. The (1-5C)heteroaryl may optionally be substituted.     Examples of “(1-5C)heteroaryl” include, but are not limited to,     tetrazolyl, imidazolyl, pyridyl, pyrimidyl, triazinyl, thienyl     furyl, pyrolyl or pyrazolyl. -   (3-6C)Cycloalkylamino means an amino group, monosubstituted with an     cycloalkyl group containing 3-6 carbon atoms having the same meaning     as previously defined. -   (1-6C)Alkylamino means an amino group, monosubstituted with an alkyl     group containing 1-6 carbon atoms having the same meaning as     previously defined. Preferred (1-6C)alkylamino group is methylamino. -   Di[(1-2C)alkyl]amino means an amino group, disubstituted with alkyl     group(s), each independently containing 1-2 carbon atoms and having     the same meaning as previously defined. Preferred     di[(1-2C)alkyl]amino group is dimethylamino. -   Di[(1-6C)alkyl]amino means an amino group, disubstituted with alkyl     group(s), each independently containing 1-6 carbon atoms and having     the same meaning as previously defined. Preferred     di[(1-6C)alkyl]amino group is N-methylpropan-1-amino. -   (2-7C)Heterocycloalkylamino means an amino group, monosubstituted     with a (2-7)heterocycloalkyl group containing 2-7 carbon atoms     having the same meaning as previously defined. -   (1-6C)Alkylaminocarbonyl means a carbonyl group substituted with an     amino group. Said amino group being monosubstituted with an alkyl     group having 1-6 carbon atoms and having the same meaning as     previously defined. -   (2-7C)Heterocycloalkylcarbonyl means a carbonyl group substituted     with an (2-7C)heterocycloalkyl group having 2-7 carbon atoms and     having the same meaning as previously defined. -   (1-5C)Alkoxycarbonyl means a carbonyl group substituted with an     alkoxy group the alkyl moiety of which having 1-6 carbon atoms as     previously defined. -   (1-6C)Alkylsulfonyl means a sulfonyl group substituted with an     (1-6C)alkyl group having 1-6 carbon atoms and having the same     meaning as previously defined. -   (1-6C)Alkylcarbonyl means a carbonyl group substituted with an     (1-6C)alkyl group having 1-6 carbon atoms and having the same     meaning as previously defined. -   (3-6C)Cycloalkylcarbonyl means a carbonyl group substituted with an     (3-6C)cycloalkyl group having 3-6 carbon atoms and having the same     meaning as previously defined. -   (1-6C)Alkylaminocarbonyl means a carbonyl group substituted with an     amino group. Said amino group being monosubstituted with an alkyl     group having 1-6 carbon atoms and having the same meaning as     previously defined. -   (1-6C)Alkylcarbonylamino means an amino group substituted with a     carbonyl group. Said carbonyl group being monosubstituted with an     alkyl group having 1-6 carbon atoms and having the same meaning as     previously defined. -   (3-6C)Cycloalkylcarbonylamino means an amino group substituted with     a carbonyl group. Said carbonyl group being monosubstituted with a     cycloalkyl group having 3-6 carbon atoms and having the same meaning     as previously defined. -   (2-7C)Heterocycloalkylcarbonylamino means an amino group substituted     with a carbonyl group. Said carbonyl group being monosubstituted     with a (2-7C)heterocycloalkyl group having 2-7 carbon atoms and     having the same meaning as previously defined. -   Hydroxy(1-2C)alkyl means a (1-2C)alkyl group having 1-2 carbon atoms     with the same meaning as previously defined, substituted with a     hydroxyl group. -   (1-2C)Alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl means a (1-6C)alkyl group     having 1-6 carbon atoms with the same meaning as previously defined,     substituted with one or more (2-4C)alkyloxy groups, wherein n     represents an integer of 1, 2, 3 or 4, the alkoxy groups being     linearly connected one to another. The last (2-4C)alkyloxy group     being substituted with an (1-2C)alkyloxy group. In the     (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl group, the preferred     (1-2C)alkoxy group is methoxy, the preferred (2-4C)alkoxy is ethoxy,     and the preferred (1-6C)alkyl is ethyl, preferably n is 1,2,3,4, n     is 1 or 2 being most preferred. -   (1-9C)heteroaryl means a substituted or unsubstituted aromatic group     having 1-9 carbon atoms and 1-4 heteroatoms selected from N, O     and/or S. The (1-9C)heteroaryl may optionally be substituted.     Examples of “(1-9C)heteroaryl” include, but are not limited to,     quinolone, isoquinoline, indazole benzisoxazole and indole. -   (2-6C)alkenyl means a branched or unbranched alkenyl group having     2-6 carbon atoms. Examples of “(2-6C)alkenyl” include, but are not     limited to, ethenyl, 2-butenyl and n-pentenyl. -   (2-6C)alkynyl means a branched or unbranched alkynyl group having     2-6 carbon atoms, Examples of “(2-6C)alkynyl” include, but are not     limited to, ethynyl, propynyl, n-butynyl, n-pentynyl, isopentynyl,     isohexynyl or n-hexynyl. -   (3-7C)heterocycloalkyl means a heterocycloalkyl group having 3-7     carbon atoms, preferably 3-5 carbon atoms, and one or two     heteroatoms selected from N, O and/or S. Examples of     “heterocycloalkyl” include, but are not limited to, azetidinyl,     pyrrolidinyl, piperidinyl, homopiperidinyl or morpholinyl. -   (4-8C)heterocycloalkenyl) means a heterocycloalkenyl group having     4-8 carbon atoms, preferably 3-5 carbon atoms having a double bond     therein; and 1 heteroatom selected from N, O and/or S. Examples of     “heteroalkenyl” include, but are not limited to, oxycyclohexenyl and     azacyclohexenyl. -   Halo(1-6C)alkyl means a branched or unbranched alkyl group having     1-6 carbon atoms, in which from one up to all hydrogen atoms are     replaced by a halogen as defined herein. Examples of such branched     or straight chain haloalkyl groups useful in the present invention     include, but are not limited to, methyl, ethyl, propyl, isopropyl,     isobutyl and n-butyl substituted independently with one or more     halogen atoms, e.g., fluoro, chloro, bromo and iodo. Specific     examples of “haloalkyl include, but are not limited to,     fluoromethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl,     2-fluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, and     perfluoro-n-propyl. -   HO(1-6C)alkyl means a branched or unbranched alkyl group having 1-6     carbon atoms, in which one, two or three hydrogen atoms are replaced     by a hydroxyl group. Examples of “HO(1-6C)alkyl” include, but are     not limited to, hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, and     1,2-dihydroxyethyl. -   H₂N(1-6C)alkyl means a branched or unbranched alkyl group having 1-6     carbon atoms, in which one, two or three hydrogen atoms are replaced     by an amino group. Examples of “H₂N(1-6C)alkyl” include, but are not     limited to, aminomethyl, 1-aminoethyl, 2-aminoethyl, and     1,2-di-aminoethyl. -   Cyano(1-6C)alkyl means a branched or unbranched alkyl group having     1-6 carbon atoms, in which one, two or three hydrogen atoms are     replaced by a cyano group. Examples of “cyano(1-6C)alkyl” include,     but are not limited to, cyanomethyl, 1-cyanoethyl, 2-cyanoethyl, and     1,2-dicyanoethyl.

In the above definitions with multifunctional groups, the attachment point is at the last group.

When, in the definition of a substituent, is indicated that “all of the alkyl groups” of said substituent are optionally substituted, this also includes the alkyl moiety of an alkoxy group.

The term “substituted” means that one or more hydrogens on the designated atom/atoms is/are replaced with a selection from the indicated group, provided that the designated atom's normal valency under the existing circumstances is not exceeded, and that the substitution results in a stable compound. Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds.

“Stable compound” or “stable structure” is defined as a compound or structure that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into an efficacious therapeutic agent.

The term “optionally substituted” means optional substitution with the specified groups, radicals or moieties.

The present invention will now be described in the following examples. These examples are intended to be illustrative of the invention, and are not intended to be limiting of the invention.

EXAMPLES

Methods

Cancer Cell Lines

To determine whether sensitivity of cancer-derived cells to TTK inhibitors correlates with the presence of a specific genomic marker, various TTK inhibitors were profiled in parallel on a panel of sixty-six cancer cell lines derived from different tumor origins and that have been characterized with respect to the expression and mutant status of various oncogenes and tumor suppressor genes (Uitdehaag, J. C. M., et al., PLoS ONE 9(3), e92146; 2014). The cancer cell lines used are listed in Table 1. All cell lines were purchased from the American Type Culture Collection (ATCC) (Manassas, Va., U.S.A.).

TABLE 1 Cancer cell lines used in drug sensitivity analysis. 769-P AN3 CA Daoy KU812 OVCAR-3 SUP-T1 786-0 AsPC-1 DLD-1 LNCaP FGC PA-1 SW48 A-172 AU-565 DoTc2 4510 LoVo RKO SW480 A-204 BT-20 DU145 LS 174T RPMI-7951 SW620 A375 BT-549 FaDu MCF7 RT4 SW948 A388 BxPC-3 HCT116 MeWo SHP-77 T24 A-427 C-33A HCT-15 MG-63 SJRH30 T986 A-498 CAL27 HS 578T MIA PaCa-2 SK-N-AS TT A-549 CCRF-CEM J82 MOLT-4 SK-N-FI U-2 OS A-707 COLO205 Jurkat E6-1 NCI-H460 SNU-C2B U-87 MG ACHN COLO829 K-562 NCI-H82 SR WA-ES-BJ

The genetic status of the thirty-one most frequently changed cancer genes in the cell line panel has been established as either ‘mutant’ or ‘wild-type’ from public sequencing data (Garnett, M. J., et al., Nature 483: 570; 2012). In Table 2 the cell lines are listed that have CTNNB1 gene mutations. A427, LS 174T, HCT116 and SW48 have mutations in the serine or threonine residues that regulates the stability of β-catenin via phosphorylation at specific serine and threonine residues (Polakis, P., Curr. Opin. Gen. Dev. 9: 15; 1999). The other cell lines listed in the table and the cell lines from the sixty-six cancer cell line panel that are not mentioned, either have CTNNB1 mutations that are not implicated in regulation of protein stability, or do not have any CTNNB1 gene mutation.

TABLE 2 CTNNB1 gene mutations in cancer cell lines included in the drug sensitivity analysis. Amino Mutations in acid Literature regulatory Cell line Codon change change Zygosity reference domain A427 121A > G T41A homozygous 1,2 Yes LS 174T 134C > T S45F 2,3 Yes HCT 116 131-133delCTT S45del heterozygous 1,2,4,5 Yes SW48 98C > A S33Y heterozygous 1,2,4,5 Yes Other C33A 1216G > A P406I heterozygous 1 no DU145 914C > G A305G homozygous 1,4 no LNCap 1154T > A I385H heterozygous 1 no T98G 526C > T B176Y heterozygous 1 no U2OS 1584-1G > A heterozygous 1 no (intronic substitution) COLO205 E562 splice diploid 4 no References 1. Cosmic Cell Lines project, status Feb. 2^(nd), 2015 2. Garnett, M. J., et al. 3. Wang, Z., et al., Cancer Res. 63: 5234; 2003 4. Cancer Cell Line Encyclopedia, status Feb. 2^(nd), 2015 5. Morin, et al., 1997; Ilyas, M., et al., Proc. Natl. Acad. Sci. USA 94: 10330; 1997 Cell Proliferation Assays

All cell lines were cultured in the media as recommended by ATCC. The culture media were purchased from Life Technologies (Bleiswijk, The Netherlands). Proliferation assays were carried out as described (Uitdehaag J. C. M., et al.) in 384-well plates with incubation with compound for 120 hours. Effects of TTK inhibitors were measured in a 9-point dilution series in duplicate. The final DMSO concentration during incubation was 0.4% (v/v) in all wells. As readout, intracellular ATP content was used as an indirect measure of cell number, using ATPlite™ 1 Step solution (Perkin Elmer, Groningen, The Netherlands). The effect of the compounds on cell growth was calculated relative to control wells containing only 0.4% (v/v) DMSO. Half maximum inhibitory potencies (IC₅₀s) were fitted by non-linear regression using XLfit™ 5 (ID Business Solutions, Ltd., Surrey, U.K.).

Analysis of Cell Panel Response Data

Analysis of variance (Anova) was used to determine whether there was a statistical correlation between a particular genetic change in the panel of cell lines and drug sensitivity. The mutations and the ¹⁰ log IC₅₀ from the cell proliferation assays were analyzed with a type II Anova analysis using the statistical program R (R Foundation for statistical computing, Vienna, Austria) and displayed in volcano plots such as shown in FIGS. 2A-2G. The p-value (y-axis in the volcano plot) indicates the confidence level for genetic association of mutations in a particular gene with a IC₅₀ shift. The average factor with which the IC₅₀ shifts is indicated on the x-axis. The areas of the circles are proportional to the number of mutants in the cell panel (each mutation is present at least twice). To compute significance, p-values were subjected to a Benjamini-Hochberg multiple testing correction (Benjamini, Y., and Hochberg, Y., J. Royal. Statistic. Soc. B 57:289; 1995). Genetic associations with a<20% false discovery rate were considered significant.

Statistical Analysis of Difference in Sensitivity

To quantify differences in sensitivity between CTNNB1-mutant and CTNNB1 proficient, the inhibitory potency of the TTK inhibitors was expressed as pIC₅₀ (−¹⁰ log IC₅₀). A two-tailed Student's t-test was performed to determine whether differences in sensitivity (ΔpIC₅₀) between CTNNB1 mutant and CTNNB1 proficient cells were statistically significant (i.e., p<0.05).

Comparison of Sensitivity in Isogenic Cell Lines

To determine whether mutated CTNNB1 was sufficient to confer increased sensitivity to TTK inhibitors, proliferation assay were performed with a pair of isogenic cell lines. Parental HCT116 cells harbor a deletion of three base pairs in one copy of the CTNNB1 gene, resulting in deletion of the regulatory serine residue at position 45 (S45del) of β-catenin (Table 2). Parental HCT116 cells are furthermore heterozygous regarding mutation in the CTNNB1 gene, i.e., the genotype of parental HCT116 regarding CTNNB1 is S45del/+. An isogenic cell line derived from HCT116 lacking the mutated CTNNB1 gene copy (+/−) was purchased from Horizon Discovery (Cambridge, U.K.) (Chan, T. A., et al., Proc. Natl. Acad. Sci. USA 99: 8265; 2002). HCT116 parental and isogenic derivatives were cultured in identical media, as recommended by the supplier. Proliferation assays were carried out as described for cancer cell lines (Uitdehaag J. C. M., et al.). Dose response curves were plotted, IC₅₀, pIC₅₀ and maximum percentage effect (efficacy) were calculated using XLfit™ 5. Difference in sensitivity of the parental and the isogenic derivative were expressed as difference in pIC₅₀ (ΔpIC₅₀) and difference in efficacy (Δefficacy).

TTK Inhibitors (Examples 1 to 31)

The following examples are illustrative embodiments of the invention, not limiting the scope of the invention in any way. Reagents are either commercially available or are prepared according to procedures in the literature.

Method LCMS (A)

Method name NTRC_C18_Short.M Column Waters XTerra C18-MS, 50 × 4.6 mm ID, 2.5 μm Flow 0.5 ml/min. Temperature 40° C. Detector DAD 210, 254, 280 nm Detector MSD API-ES MSD signal 1 2 Mode Scan Scan Polarity Positive Negative Mass Range 100-1000 m/z 100-1000 m/z Fragmentor 70 70 Cycle Time 50% 50% Sample N/A preparation Concentration 1 mg/ml in MeOH or CAN Injection volume 1.0 μl Eluent A B Time % 0.1% Formic % 0.05% Formic Acid in [min] Acid Acetonitrile 0 90 10 0.3 90 10 7.0 10 90 7.1 90 10 10.0 90 10 Post time 0.2 min Stop time 10 min Method LCMS (B)

Method name NTRC_C18.M Column Waters XTerra C18-MS, 50 × 4.6 mm ID, 2.5 μm Flow 0.5 ml/min. Temperature 40° C. Detector DAD 210, 254, 280 nm Detector MSD API-ES MSD signal 1 2 Mode Scan Scan Polarity Positive Negative Mass Range 100-1000 m/z 100-1000 m/z Fragmentor 70 70 Cycle Time 50% 50% Sample N/A preparation Concentration 1 mg/ml in MeOH or CAN Injection volume 1.0 μl Eluent A B Time % 0.1% % 0.05% Formic Acid in [min] Formic Acid Acetonitrile 0 90 10 1 90 10 22.0 10 90 22.1 90 10 30.0 90 10 Post time 0.2 min Stop time 30 min Method LCMS (C)

LC System HP1200SL Column Agilent Eclipse plus C18 150 mm × 2.1 mm ID 3.5 μm Column temperature 40° C. Sample(s) ca 1 mg/mL Autosampler 20° C. temperature Injection volume 5 μl Flow 0.5 ml/min Type of Pump Binary Eluent A = MilliQ + 0.1% Formic Acid B = Acetonitrile time (min) % A % B Gradient 0 90 10 1 90 10 22 10 90 22.1 90 10 30 90 10 Next Injection delay 0 min UV detection UV 210, 240, 280 nm Flowcell DAD 10 mm

MS system Agilent 6130 single Quad MS Source ESI Mode Positive (+) Mass range 100-1000 Da Flow The total flow was split to a suitable flow infused directly in the APCI/ESI multimode source of the Agilent 6130 Method Preparative HPLC

LC System Waters Prep System Column Phenomenex Luna, C18(2) 100 A, 150 mm × 21.2 mm, 5 μm Column Temp 20° C. Sample(s) 10-50 mg Autosamp. Temp 20° C. Injection volume 500-950 μL Flow 15 ml/min Eluent A = MilliQ + MeCN (9/1) B = Acetonitrile time (min) % A % B % C Gradient 0 97 0 3 20 37 60 3 25 37 60 3 25.1 97 0 3 30 97 0 3 UV detection Photo Diode Array

The following abbreviations are used throughout the application with respect to chemical terminology:

-   TFA Trifluoracetic acid -   HATU     O-(7-Azabenzotriazol-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate -   DMF N,N-Dimethylformamide -   THF Tetrahydrofuran -   MeOH Methanol -   EtOAc Ethyl acetate -   DCM Dichloromethane -   Na₂SO₄ Sodium sulfate -   TMS-Cl Chlorotrimethylsilane -   DiPEA N,N-Diisopropylethylamine -   EtOH Ethanol -   10% Pd/C 10% Palladium on charcoal -   HPLC High Performance Liquid Chromatography -   LCMS Liquid Chromatography with Mass Spectrometry detection -   NaOH Sodium hydroxide -   KOH Potassium hydroxide -   HCl Hydrogen chloride -   NaHCO₃ Sodium bicarbonate -   4-DMAP 4-Dimethylamino pyridine -   Boc tert-Butyloxycarbonyl -   Cbz Benzyloxycarbonyl -   HNO₃ Nitric acid -   LiHMDS Lithium bis(trimethylsilyl)amide -   DDQ 2,3-Dichloro-5,6-dicyano-p-benzoquinone -   DEAD Diethyl azodicarboxylate -   o/n overnight

The names of the final products in the examples are generated using Accelrys Draw (version 4.1).

Example 1 (WITJ0018D)

N6-cyclohexyl-N2-(2-methyl-4-morpholino-phenyl)-9H-purine-2,6-diamine

This compound was prepared as described in WO2010/111406 A2 and Bioorg. Med. Chem. Letters 22 (2012) 4377. Purification was performed using preparative HPLC to afford the title compound (338 mg). Data: LCMS (C) R_(t): 10.995 min; m/z 408.3 (M+H)⁺.

Example 2 JGS0282C)

N-cyclopropyl-4-[8-(isobutylamino)imidazo[1,2-a]pyrazin-3-yl]benzamide

This compound was prepared as described in WO2012/080229 A1 and Cell Death and Differentiation 20 (2013), 1532. Purification was performed using preparative HPLC to afford the title compound (47 mg). Data: LCMS (B) R_(t): 8.088 min; m/z 350.2 (M+H)⁺.

Example 3 (BTHO238B)

N-(2,6-diethylphenyl)-1-methyl-8-[4-[(1-methyl-4-piperidyl)carbamoyl]-2-(trifluoromethoxy)anilino]-4,5-dihydropyrazolo[4,3-h]quinazoline-3-carboxamide

This compound was prepared as described in WO2009/156315 A1 and Cancer Res. 70 (2010), 10255. Purification was performed using preparative HPLC to afford the title compound (191 mg). Data: LCMS (A) R_(t): 5.810 min; m/z 677.6 (M+H)⁺.

Example 4 (WITJ113B)

N-(2,6-diethylphenyl)-8-(2-methoxy-4-piperazin-1-yl-anilino)-1-methyl-4,5-dihydropyrazolo[4,3-h]quinazoline-3-carboxamide

This compound was prepared as described in WO2009/156315 A1. Purification was performed using preparative HPLC to afford the title compound (7.3 mg). Data: LCMS (C) R_(t): 12.954 min; m/z 567.3 (M+H)⁺.

Example 5 (JGS0716D)

N-cyclopropyl-4-[6-(2,3-difluoro-4-methoxy-phenoxy)-8-(tetrahydropyran-4-ylmethylamino)imidazo[1,2-b]pyridazin-3-yl]-2-methyl-benzamide

This compound was prepared as described in WO 2014/131739 A1. Purification was performed using preparative HPLC to afford the title compound (90 mg). Data: LCMS (B) R_(t): 13.496 min; m/z 564.5 (M+H)⁺.

Example 6 (JGS0728A)

N-cyclopropyl-4-[6-(3-fluoro-4-methoxy-phenoxy)-8-(oxetan-3-ylmethylamino)imidazo[1,2-b]pyridazin-3-yl]-2-methyl-benzamide

This compound was prepared as described in WO 2014/131739 A1. Purification was performed using preparative HPLC to afford the title compound (45 mg). Data: LCMS (B) R_(t): 11.640 min; m/z 518.4 (M+H)⁺.

Intermediate 1

Ethyl 2-chloro-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (a) 5-Bromo-2-chloro-pyrimidin-4-amine (WITJ0221)

To a solution of 5-bromo-2,4-dichloro-pyrimidine (150 g; 658 mmol) in THF (445 mL) was added ammonium hydroxide (25% in water, 250 mL) and the resulting reaction mixture was stirred at room temperature for 90 min. The mixture was subsequently concentrated in vacuo to a small volume and partitioned between ethyl acetate and water. The organic phase was separated and washed with water and brine, dried over sodium sulfate, filtered and concentrated to give 137.3 g (quant. yield) of 5-bromo-2-chloro-pyrimidin-4-amine.

(b) 5-Bromo-2-methoxy-pyrimidin-4-amine (WITJ0223)

To a suspension of 5-bromo-2-chloro-pyrimidin-4-amine (137.3 g, 658 mmol) in methanol (1 L) was added portion-wise sodium methoxide (83.5 g; 1.54 mol). The reaction mixture was stirred for 2 h. at reflux. The reaction mixture was concentrated to a small volume (˜400 mL) and poured into a saturated solution of ammonium chloride in water (1.2 L). This mixture was allowed to stir for 15 min, after which the water layer was extracted with ethyl acetate. The combined ethyl acetate layers were washed with brine, dried over sodium sulfate, filtered and concentrated to yield 5-bromo-2-methoxypyrimidin-4-amine (133.7 g, 99.4%).

(c) Ethyl (E)-3-(4-amino-2-methoxy-pyrimidin-5-yl)prop-2-enoate 256) (WITJ0256)

Palladium(II) acetate (1.21 g, 5.5 mmol) and triphenylphosphine (3.40 g, 13.0 mmol) were dissolved in anhydrous and oxygen-free DMF (53 mL) and stirred for 5 min at 30° C. to give an orange suspension. To this suspension was added a solution of 5-bromo-2-methoxypyrimidin-4-amine (44.1 g, 216 mmol) in DMF (270 mL), triethylamine (60.2 mL, 432 mmol) and a solution of ethyl acrylate (23.5 mL, 216 mmol) in DMF (50 mL). The reaction mixture was stirred at 100° C. o/n under a nitrogen atmosphere. The reaction mixture was evaporated to a small volume. Water (300 mL) and brine (300 mL) were added to the mixture, followed by an extraction with ethyl acetate (300 mL, twice). The combined organic layers were washed with water, brine, dried over sodium sulfate and concentrated in vacuo. The crude product was purified by silica column chromatography (ethyl acetate:heptane=2:1 v/v %) to yield the title compound (38.2 g, 77%).

(d) 2-Methoxy-6,8-dihydro-5H-pyrido[2,3-d]pyrimidin-7-one (WITJ0262)

To a stirred solution of ethyl (E)-3-(4-amino-2-methoxy-pyrimidin-5-yl)prop-2-enoate (12.52 g, 56.1 mmol) in methanol (250 mL) was added a suspension of 10% Pd on charcoal (1.19 g) in methanol/ethanol=3/1 v/v % (30 mL). The reaction mixture was stirred at room temperature for 15 min under nitrogen atmosphere. Then, ammonium formate (35.3 g, 561 mmol) was added and the resulting reaction mixture was refluxed o/n. After cooling of the reaction mixture, a fresh portion of ammonium formate (20 g, 317 mmol) was added and stirring was continued an additional night at reflux. The reaction mixture was filtered over Decalite® and the Pd—C/Decalite® residue was washed with dichloromethane/methanol=8/2 v/v % and the filtrate was concentrated in vacuo. The residue was dissolved in dichloromethane and washed with water, dried over sodium sulfate, filtered and concentrated in vacuo to obtain 9.4 g (94%) of 2-methoxy-6,8-dihydro-5H-pyrido[2,3-d]pyrimidin-7-one.

(e) Ethyl 2-methoxy-5,6,8,9-tetrahydropyrimido[4,5-e]indolizine-7-carboxylate (JGS0241)

2-Methoxy-6,8-dihydro-5H-pyrido[2,3-d]pyrimidin-7-one (4.79 g, 26.8 mmol) was suspended in THF (200 mL) in a three-necked flask (500 mL), equipped with a mechanical stirrer, a thermometer and a reflux condenser. The mixture was cooled to 0° C. and sodium hydride (60% dispersion in oil, 1.18 g, 29.4 mmol) was added in two batches. The mixture was stirred at 0° C. for 30 min. (1-ethoxycarbonylcyclopropyl)triphenylphosphonium tetrafluoroborate (13.6 g, 29.4 mmol) was added and the resulting suspension was heated to reflux and kept at reflux temperature for 3 days. The reaction mixture was cooled to room temperature and poured in a 1/1/1 mixture of brine/water/EtOAc (450 mL). The water layer was extracted with ethyl acetate (2×). The combined organic layers were washed with water and brine, dried over sodium sulfate, filtered and concentrated in vacuo to give 18.05 g of an orange oil. The crude product was used directly in the next step without purification.

(f) Ethyl 2-methoxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (JGS244)

To a stirred solution of ethyl 2-methoxy-5,6,8,9-tetrahydropyrimido[4,5-e]indolizine-7-carboxylate (18.05 g, 26.2 mmol) in dichloromethane (100 mL) was added acetic acid (3.15 g, 3 mL) and lead(IV)acetate (13.9 g, 31.4 mmol). The reaction mixture was stirred for 2 h at room temperature then filtered over a PE filter to remove Pb-salts and the Pb-residue was washed with 2×30 mL DCM. The filtrate was concentrated in vacuo and the resulting residue was dissolved in ethyl acetate (300 mL). A solution of sodium bicarbonate (5%) was added until pH˜8.5. Both the organic and the water layers were filtered over Decalite® to remove any remaining salts. The water layer was subsequently extracted with EtOAc (2×50 mL). The combined organic layers were washed with 5% sodium bicarbonate-solution (100 mL), water (100 mL), brine (50 mL), dried (Na₂SO₄), filtered and concentrated in vacuo. The crude product was purified by column chromatography on silica (heptane: ethyl acetate=I/O to 1/1 v/v %) to yield the title compound (4.74 g, 66% over two steps).

(g) Ethyl 2-hydroxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (JGS0245)

Sodium iodide (7.83 g, 52.2 mmol) was added to a stirred solution of ethyl 2-methoxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (4.74 g, 17.3 mmol) in acetonitrile (150 mL). Trimethylsilyl chloride (5.64 g, 6.59 mL) dissolved in acetonitrile (30 mL) was added drop-wise to the reaction mixture and the mixture was stirred at room temperature o/n. NaI (1 eq) was added and additional TMS-Cl (0.94 g, 1.1 mmol) in acetonitrile (6 mL) was added drop-wise and the reaction was stirred for 3 days at room temperature. The mixture was concentrated and the residue was suspended in 200 mL DCM/MeOH (4/1) and extracted with a mixture of saturated solution of sodium thiosulfate (200 mL) and water (200 mL). The water layer was extracted with 3×150 mL DCM/MeOH (4/1). The combined organic layers were dried over sodium sulfate, filtered and the solvent was removed under reduced pressure to give a yellow solid. The residue was dried at 40° C. under vacuum for 18h to give 3.89 g ethyl 2-hydroxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (86%).

(h) Ethyl 2-chloro-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (Intermediate 1) (JGS0278)

N,N-dimethylaniline (182 mg, 191 uL, 1.50 mmol) was added to a solution of ethyl 2-hydroxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (3.89 g, 15.0 mmol) in acetonitrile (100 mL). A solution of phosphorus(V) oxychloride (11.5 g, 7.00 mL, 75.0 mmol) in acetonitrile (15 mL) was added drop-wise to the reaction mixture. The yellow suspension was heated for 4 hours to 65° C. during which the suspension turned into a clear solution. After cooling, the mixture was slowly poured in a stirred mixture of 25% aq. ammonia (200 mL, 86.7 eq.) and ice-water (250 mL) keeping the temperature below 10° C. in 15-20 minutes. After stirring for another 15 minutes the solids were filtered. The solids were dissolved in 200 mL EtOAc and washed with brine (20 mL). The organic layer was dried over sodium sulfate, and concentrated in vacuo to give an off-white solid. The crude product was purified by column chromatography on silica (heptane/ethyl acetate=1/0 to 1/1 v/v %) to yield the title compound (3.05 g, 73%).

Intermediate A

Benzyl 4-(4-amino-3-methyl-phenyl) piperazine-1-carboxylate (a) Benzyl 4-(3-methyl-4-nitro-phenyl)piperazine-1-carboxylate (WITJ404)

Benzyl piperazine-1-carboxylate (1.05 mL, 5.25 mmol) and potassium carbonate (1.38 g, 10 mmol) were added to a solution of 4-fluoro-2-methyl-1-nitro-benzene (776 mg, 5 mmol) in DMF (10 mL) and the resulting mixture was stirred at 100° C. for 18 h. Water was added to the reaction mixture and extraction performed with ethyl acetate. The combined organic layers were washed with brine, dried over sodium sulfate and concentrated in vacuo. The crude product was purified by silica column chromatography (heptane/ethyl acetate=I/O to 6/4 v/v %) to yield the title compound (1.75 g, 98%).

(b) Benzyl 4-(4-amino-3-methyl-phenyl) piperazine-1-carboxylate (Intermediate A) (WITJ406)

Benzyl 4-(3-methyl-4-nitro-phenyl)piperazine-1-carboxylate (355 mg, 1 mmol) was dissolved in THF (5 mL) and acetic acid (1.1 mL) was added. The mixture was cooled to 0° C. and zinc (1.31 g, 20 mmol) was added in small portions to keep the temperature below 20° C. The reaction mixture was stirred at room temperature o/n. After TLC analysis indicated a complete conversion of the starting material, the mixture was filtered over Decalite® and the Zn-Decalite® residue was washed with EtOAc (20 mL). The combined filtrates were washed with a 1N NaOH-solution (25 mL), followed by water (25 mL) and brine (25 mL). The organic layer was dried (Na₂SO₄), filtered and concentrated in vacuo to give benzyl 4-(4-amino-3-methyl-phenyl)piperazine-1-carboxylate (327 mg, quantitative).

Intermediate 2

Benzyl 4-[4-[(7-chlorocarbonyl-5,6-dihydropyrimido[4,5-e]indolizin-2-yl)amino]-3-methyl-phenyl]piperazine-1-carboxylate (a) Ethyl 2-[4-(4-benzyloxycarbonylpiperazin-1-yl)-2-methyl-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (WITJ407)

To a suspension of ethyl 2-chloro-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (Intermediate 1, 292 mg, 1.05 mmol) in n-butanol (8 mL) was added benzyl 4-(4-amino-3-methyl-phenyl)piperazine-1-carboxylate (Intermediate A, 327 mg, 1.0 mmol) and trifluoroacetic acid (153 L 2.0 mmol). The reaction mixture was heated for 12 hours at 120° C. under microwave radiation. The reaction mixture was concentrated in vacuo and the residue was dissolved in ethyl acetate. The organic layer was washed with a saturated solution of sodium bicarbonate, dried over sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by silica column chromatography (heptane/ethyl acetate=4/6 to 0/1 v/v %). Fractions containing product were collected and evaporated to afford ethyl 2-[4-(4-benzyloxycarbonylpiperazin-1-yl)-2-methyl-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (423 mg, 75% yield).

(b) Benzyl 4-[4-[(7-chlorocarbonyl-5,6-dihydropyrimido[4,5-e]indolizin-2-yl)amino]-3-methyl-phenyl]piperazine-1-carboxylate (Intermediate 2) (WITJ408/WITJ414)

To a solution of ethyl 2-[4-(4-benzyloxycarbonylpiperazin-1-yl)-2-methyl-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (423 mg, 0.75 mmol) in 15 mL absolute ethanol was added a 2M NaOH-solution (935 μL (2.5 eq). 1.87 mmol). The reaction mixture was heated at 65° C. o/n. Reaction mixture was evaporated to dryness and dried under high vacuum. The resulting residue was dissolved in water, stirred o/n at room temperature and lyophilised to yield the crude sodium 2-[4-(4-benzyloxycarbonylpiperazin-1-yl)-2-methyl-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate.

Thionyl chloride (561 μL, 7. mmol) was added to a cold (0° C.) suspension of the crude sodium 2-[4-(4-benzyloxycarbonylpiperazin-1-yl)-2-methyl-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (217 mg, 0.39 mmol theor.) in dichloromethane (8 mL). The resulting slurry was stirred at room temperature o/n. The reaction mixture was concentrated in vacuo and the residue was co-evaporated with toluene (2×10 mL) to give of benzyl 4-[4-[(7-chlorocarbonyl-5,6-dihydropyrimido[4,5-e]indolizin-2-yl)amino]-3-methyl-phenyl]piperazine-1-carboxylate as a yellow/brown powder (261 mg, quant. crude yield).

Example 7 (WITJ0416/WITJ429A)

N-(2,6-dimethylphenyl)-2-(2-methyl-4-piperazin-1-yl-anilino)-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

To a suspension of benzyl 4-[4-[(7-chlorocarbonyl-5,6-dihydropyrimido[4,5-e]indolizin-2-yl)amino]-3-methyl-phenyl]piperazine-1-carboxylate (Intermediate 2, 45 mg, 0.081 mmol theor.) in acetonitrile (3 mL) was added 2,6-dimethylaniline (15 μL, 0.12 mmol) and a catalytic amount of 4-DMAP. The reaction mixture was stirred at 50° C. for 1 h. After evaporation of the solvent, the Cbz-group was de-protected using TFA/thioanisole and the crude product was purified by preparative HPLC. Fractions containing product were collected and concentrated in vacuo. The residue was partitioned between dichloromethane and 5% NaHCO₃-solution. The organic phase was separated over a PE-filter and evaporated to afford the title compound (20 mg, 64%). Data: LCMS (B) R_(t): 9.706 min; m/z 508.3 (M+H)⁺.

Example 8 (JGS439C)

N-(2,6-dimethylphenyl)-2-[2-methoxy-4-(tetrahydropyran-4-ylcarbamoyl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide (a) 2-(4-Bromo-2-methoxy-anilino)-N-(2,6-dimethylphenyl)-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide (JGS453)

This compound was prepared from its corresponding acid chloride, using the same sequence of reactions, as described for Intermediate 2, using commercially available 4-bromo-2-methoxyaniline as starting material. The acid chloride was subsequently reacted with 2,6-dimethylaniline according to procedures described in Example 7 to afford the title compound (1.35 g, 84%).

(b) 2-(4-Cyano-2-methoxy-anilino)-N-(2,6-dimethylphenyl)-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide (JGS455)

To a solution of 2-(4-bromo-2-methoxy-anilino)-N-(2,6-dimethylphenyl)-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide (1.35 g, 2.6 mmol) and zinc cyanide (321 mg, 2.73 mmol) in DMF (4 mL) was added tetrakis(triphenylphosphine)palladium(0) (300 mg, 0.26 mmol). The reaction mixture was heated for 30 minutes at 170° C. under microwave radiation. After cooling to ambient temperature, the mixture was concentrated and the residue was diluted with ethyl acetate, washed with water and brine, dried over sodium sulfate, filtered and concentrated in vacuo to afford the crude title compound (1.05 g, 87%).

(c) 4-[[7-[(2,6-Dimethylphenyl)carbamoyl]-5,6-dihydropyrimido[4,5-e]indolizin-2-yl]amino]-3-methoxy-benzoic acid (JGS0457)

To a stirred suspension of 2-(4-cyano-2-methoxy-anilino)-N-(2,6-dimethylphenyl)-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide (750 mg, 1.61 mmol) in MeOH (25 mL) was added a solution of potassium hydroxide (453 mg, 8.07 mmol) in water (12.5 mL). The reaction mixture was heated for 2 hours at 120° C. under microwave radiation. After evaporation of the methanol fraction, the resulting water layer was acidified by addition of 2N HCl-solution until pH-2. After extraction with dichloromethane, the combined organic layers were filtered over a PE-filter to give 330 mg of the title compound (yield: 42%).

(d)N-(2,6-dimethylphenyl)-2-[2-methoxy-4-(tetrahydropyran-4-ylcarbamoyl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide (JGS439C)

4-[[7-[(2,6-Dimethylphenyl)carbamoyl]-5,6-dihydropyrimido[4,5-e]indolizin-2-yl]amino]-3-methoxy-benzoic acid (30 mg, 0.062 mmol) was dissolved in N,N-dimethylformamide (3 ml). HATU (25.9 mg, 0.068 mmol) and N,N-diisopropylethylamine (43.1 μL, 0.25 mmol) were subsequently added and the mixture was stirred for 10 min at room temperature. 4-Aminotetrahydropyran hydrochloride (12.8 mg, 0.093 mmol) was added and the mixture was stirred at room temperature o/n. The mixture was poured into a mixture ethyl acetate/water/brine (1/1/1) and stirred for 15 min. The organic layer was separated, washed with brine, dried over sodium sulphate filtered and concentrated in vacuo. Purification was performed using preparative HPLC to afford the title compound (5 mg, 18%). Data: LCMS (B) R_(t): 14.407 min; m/z 567.3 (M+H)⁺.

Intermediate B (NV0068/NV0076)

2-Methoxy-4-(1,3,5-trimethylpyrazol-4-yl)aniline (a) tert-Butyl N-[2-methoxy-4-(1,3,5-trimethylpyrazol-4-yl)phenyl]carbamate (NV0068)

A mixture of tert-butyl N-(4-bromo-2-methoxy-phenyl)carbamate (150 mg, 0.5 mmol), 1,3,5-trimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrazole (118 mg, 0.5 mmol), tetrakis(tri-phenylphosphine)palladium(0) (58 mg, 0.05 mmol) and potassium carbonate (207 mg, 1.5 mmol) in dioxane (4 mL) was heated at 100° C. under microwave irradiation for 20 minutes in a sealed tube. After cooling to ambient temperature, the mixture was concentrated and the residue was diluted with ethyl acetate, washed with water and brine, dried over sodium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography (heptane/ethyl acetate=100/0 to 25/75 v/v %) to afford tert-butyl N-[2-methoxy-4-(1,3,5-trimethylpyrazol-4-yl)phenyl]carbamate (126.8 mg, 77%).

(b) 2-Methoxy-4-(1,3,5-trimethylpyrazol-4-yl)aniline (Intermediate B) (NV0076)

tert-Butyl N-[2-methoxy-4-(1,3,5-trimethylpyrazol-4-yl)phenyl]carbamate (127 mg, 0.38 mmol) was dissolved in DCM (2 mL). TFA (3 mL) was added and the reaction mixture was stirred for 1 hour at room temperature. The mixture was concentrated in vacuo to give a brown oil (313 mg) that was used without further purification.

Intermediate C (JDM0438/JDM035)

1-[2-[2-(2-Methoxyethoxy)ethoxy]ethyl]-3,5-dimethyl-pyrazol-4-amine (a) 1-[2-[2-(2-Methoxyethoxy)ethoxy]ethyl]-3,5-dimethyl-4-nitro-pyrazole

To a cold (0° C.) solution of 3,5-dimethyl-4-nitro-1H-pyrazole (250 mg, 1.77 mmol), triethylene glycol monomethylether (482 μL, 3.01 mmol) and triphenylphosphine (789 mg, 3.01 mmol) in THF (10 mL) was added dropwise a solution of 40% DEAD in toluene (1.31 mL, 3.01 mmol) The reaction mixture was allowed to warm to room temperature and was stirred for 3 h. Ethyl acetate was added and washed with a 10% NaCl-solution. The organic layer was dried (Na₂SO₄), filtered and concentrated. The residue was purified by column chromatography (DCM/MeOH=99/1 to 95/5 v/v %) to afford 1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]-3,5-dimethyl-4-nitro-pyrazole (1.7 g, crude) which was used without purification in the next step.

(b) 1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]-3,5-dimethyl-pyrazol-4-amine (Intermediate C)

1-[2-[2-(2-Methoxyethoxy)ethoxy]ethyl]-3,5-dimethyl-4-nitro-pyrazole (1.5 g, 1.77 mmol theor.) was dissolved in THF (15 mL) and acetic acid (1.6 mL) was added. The mixture was cooled to 0° C. and zinc (2.3 g, 35.4 mmol) was added in small portions keeping the temperature below 20° C. The reaction mixture was stirred at room temperature o/n. After TLC analysis indicated a complete conversion of the starting material, the mixture was filtered over Decalite® and the Zn-Decalite® residue was washed with ethyl acetate. The combined filtrates were washed with a 1N NaOH-solution, followed by water and brine. The organic layer was dried (Na₂SO₄), filtered and concentrated in vacuo. The residue was dissolved in methanol and then filtered over a SCX-2 column. After rinsing the column with methanol, the desired product was eluted with an 0.7 N ammonia/methanol solution to give the title compound (340.1 mg, 74.7%).

Example 9 (JDM0641A)

N-[1-[2-[2-(2-methoxyethoxyethoxy]ethyl]-3,5-dimethyl-pyrazol-4-yl]-2-[2-methoxy-4-(1,3,5-trimethylpyrazol-4-yl) anilino]-5,6-dihydropyrimido[45-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate B as starting material. The carboxylic acid was subsequently reacted with Intermediate C in an analogous manner as described for Example 8d. Purification was performed using preparative HPLC to afford the title compound (19.5 mg, 42.6%). Data: LCMS (B) R_(t): 10.946 min; m/z 684.7 (M+H).

Intermediate D (JGS88/92)

2-Methoxy-4-(4-methylpiperazin-1-yl)aniline

This compound was prepared in an analogous manner as described for Intermediate A, starting from N-methylpiperazine and 2-methoxy-4-fluoronitrobenzene to afford the title compound (1.38 g, 94%).

Example 10 (JDM0443A)

N-[1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]-3,5-dimethyl-pyrazol-4-yl]-2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid chloride, using the same sequence of reactions, as described for Intermediate 2, using Intermediate D as starting material. The acid chloride was subsequently reacted with Intermediate C according to procedures described in Example 8d. Purification was performed using preparative HPLC to afford the title compound (11.6 mg, 28.6%). Data: LCMS (B) R_(t): 6.985 min; m/z 674.3 (M+H)⁺.

Example 11 (JGS79C)

N-(2,6-diethylphenyl)-2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding ester, using the same sequence of reactions as described for Intermediate 2a using Intermediate D as starting material. LiHDMS (1M in THF/ethylbenzene, 412 μL, 0.412 mmol) was added to a cold (0° C.) solution of 2,6-diethylaniline (50.8 μL, 0.31 mmol) in THF (1 mL). After 15 minutes of stirring at 0° C., ethyl 2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (48 mg, 0.103 mmol) in THF (2 mL) was added drop-wise to the reaction mixture and stirring was continued for 90 min at 0° C. Additional LiHMDS (100 μL) was added drop-wise at room temperature and stirring was continued for 2 hours at room temperature. The reaction mixture was quenched with 20 mL saturated solution of ammonium chloride and extracted with ethyl acetate. The combined organic layers were washed with water, brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification was performed using preparative HPLC to afford the title compound (13.5 mg, 23.2%). Data: LCMS (C) R_(t): 12.686 min; m/z 566.4 (M+H)⁺.

Intermediate E (/WITJ437WITJ438/WITJ440)

2-(Difluoromethoxy)-4-(4-methylpiperazin-1-yl)aniline

To a solution of 5-fluoro-2-nitro-phenol (500 mg, 3.18 mmol) in DMF (6 ml) was added sodium 2-chloro-2,2-difluoro-acetate (970 mg, 6.36 mmol) and disodium carbonate (405 mg, 3.82 mmol). The reaction mixture was stirred at 100° C. for 3.5 hours and subsequently at room temperature for 3 days. A 4M HCl-solution was added until a clear solution was obtained and the mixture was stirred for 2 h at room temperature. The reaction mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with 1M NaOH-solution, brine, dried over sodium sulphate, filtered and concentrated in vacuo. The residue was purified by column chromatography (heptane/ethyl acetate=10/0 to 8/2 v/v %) to afford 2-(difluoromethoxy)-4-fluoro-1-nitro-benzene (493 mg, 75%).

The title compound was prepared in an analogous manner as described for Intermediate A, starting from N-methylpiperazine and 2-(difluoromethoxy)-4-fluoro-1-nitro-benzene to afford 180 mg (80%).

Intermediate F (JDM300/WITJ410/WITJ411/WITJ413)

3,5-Diethyl-1H-pyrazol-4-amine (a) 3,5-Diethyl-1H-pyrazole

To a solution of 3,5-heptanedione (2 g, 15.6 mmol) and hydrazine hydrate (0.77 g, 15.8 mmol) in water (10 mL) was added acetic acid (1 drop) and the reaction mixture was heated to reflux for 1 h. The reaction mixture was then cooled, and concentrated under reduced pressure to provide 1.8 g of the title compound. This compound was used directly in the next step without purification.

(b) 3,5-Diethyl-4-nitro-1H-pyrazole

To a cold (0° C.) mixture of 3,5-diethyl-1H-pyrazole (1.8 g, 14.5 mmol) and concentrated sulphuric acid (1.5 ml) was added slowly, under vigorous stirring, fuming HNO₃ (4.35 ml). The reaction mixture was stirred overnight at 60° C. The mixture was subsequently cooled to room temperature, then carefully added to an ice-cold saturated solution of sodium bicarbonate and stirred for 15 min. The mixture was then extracted three times with EtOAc and combined organic layers were washed with brine, dried over sodium sulphate, filtered and evaporated in vacuo to give: 2.52 g 3,5-diethyl-4-nitro-1H-pyrazole.

(c) 3,5-Diethyl-1H-pyrazol-4-amine (Intermediate F)

The title compound was prepared in an analogous manner as described for Intermediate C, starting from 3,5-diethyl-4-nitro-1H-pyrazole to give 3,5-diethyl-1H-pyrazol-4-amine (174 mg, 71%).

Example 12 (WITJ453B)

N-(3,5-diethyl-1H-pyrazol-4-yl)-2-[2-(difluoromethoxy)-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding carboxylic acid, using the same sequence of reactions as described for Intermediate 2b, using Intermediate E as starting material. The carboxylic acid was subsequently reacted with Intermediate F in an analogous manner as described for Example 8d. Purification was performed using preparative HPLC to afford the title compound (9.6 mg, 23%). Data: LCMS (B) R_(t): 8.864 min; m/z 592.3 (M+H)⁺.

Intermediate G (JDM617/JDM622/JDM630)

3,5-Diethyl-1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]pyrazol-4-amine

The title compound was prepared in an analogous manner as described for Intermediate C, starting from 3,5-diethyl-4-nitro-1H-pyrazole (Intermediate Fb) and triethylene glycol monomethyl ether to give 660 mg of 3,5-diethyl-1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]pyrazol-4-amine (41.7%).

Intermediate M (WITJ461/WITJ4587)

Benzyl 4-(4-amino-3-methoxy-phenyl)piperazine-1-carboxylate

This compound was prepared in an analogous manner as described for Intermediate A, starting from benzyl piperazine-1-carboxylate and 2-methoxy-4-fluoronitrobenzene to afford the title compound (1.2 g, 95%).

Example 13 (JDM0684A)

N-[3,5-diethyl-1-[2-[2-(2-methoxyethoxy) ethoxy]ethyl]pyrazol-4-yl]-2-[2-methoxy-4-[4-(2-methoxyacetyl)piperazin-1-yl]anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding amine (prepared as described for Example 7 starting from Intermediate 1 and Intermediate M) and methoxyacetic acid, using standard HATU-coupling procedures as described in Example 8d. Purification was performed using preparative HPLC to afford the title compound (17.8 mg, 57.1%). Data: LCMS (B) R_(t): 9.908 min; m/z 760.8 (M+H)⁺.

Intermediate H (JDM221/JDM0222/JDM393)

1-(2-Methoxyethyl)-3,5-dimethyl-pyrazol-4-amine (a) 1-(2-Methoxyethyl)-3,5-dimethyl-4-nitro-pyrazole

To a solution of 3,5-dimethyl-4-nitro-1H-pyrazole (2.5 g, 17.7 mmol) and caesium carbonate (6.06 g, 18.6 mmol) in DMF (50 mL) was added 2-bromoethyl methyl ether (2.59 g, 1.75 mL, 18.6 mmol). The mixture was heated at 100° C. for 3.5 h. After cooling to room temperature, the mixture was poured into water and extracted with ethyl acetate (3×50 mL). The combined organic layers were washed with brine (50 mL), dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography (EtOAc/heptanes=1/4 v/v %) to afford 1-(2-methoxyethyl)-3,5-dimethyl-4-nitro-pyrazole (2.66 g, 75.4%) as a white crystalline solid.

(b) 1-(2-Methoxyethyl)-3,5-dimethyl-pyrazol-4-amine

1-(2-Methoxyethyl)-3,5-dimethyl-4-nitro-pyrazole (245 mg, 1.22 mmol) was dissolved in methanol (25 mL). The resulting solution was hydrogenated using a H-Cube continuous-flow hydrogenation reactor, 10% Pd/C, at 30° C., 8-10 bar, 1 mL/min, full H₂ modus. The resulting solution was concentrated in vacuo to yield 208 mg (quant. yield) of the title compound as a light-brown oil.

Intermediate I (JDM464/JDM450)

3,5-Diethyl-1-[2-(2-methoxyethoxy)ethyl]pyrazol-4-amine

The title compound was prepared in an analogous manner as described for Intermediate H, starting from 3,5-diethyl-4-nitro-1H-pyrazole (Intermediate Fb) and 1-bromo-2-(2-methoxyethoxy)-ethane to give 290 mg of 3,5-diethyl-1-[2-(2-methoxyethoxy)ethyl]pyrazol-4-amine (72.2%.).

Example 14 (JDM0466A)

N-[3,5-diethyl-1-[2-(2-methoxy)ethyl]pyrazol-4-yl]-2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid chloride, using the same sequence of reactions, as described for Intermediate 2, using Intermediate D as starting material. The acid chloride was subsequently reacted with Intermediate I according to procedures described in Example 7. Purification was performed using preparative HPLC to afford the title compound (22 mg, 54.4%). Data: LCMS (B) R_(t): 7.845 min; m/z 658.3 (M+H).

Intermediate J (WITJ277/WITJ84)

tert-Butyl 4-(4-amino-3-methoxy-phenyl)piperazine-1-carboxylate

This compound was prepared in an analogous manner as described in Intermediate A, starting from tert-butyl piperazine-1-carboxylate and 2-methoxy-4-fluoronitrobenzene to afford the title compound (245 mg, 91%).

Example 15 (WITJ349B)

N-[1-(2-m ethoxy yl-3,5-dimethyl-pyrazol-4-yl]-2-(2-methoxy-4-piperazin-1-yl-anilino)-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

Ethyl 2-chloro-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (Intermediate 1, 296 mg, 1.07 mmol), tert-Butyl 4-(4-amino-3-methoxy-phenyl)piperazine-1-carboxylate (Intermediate J, 328 mg, 1.07 mmol) and cesium carbonate (1.39 g, 4.27 mmol) were suspended in dioxane (25 mL). Nitrogen was bubbled through the mixture at 30° C. for 5 minutes followed by the addition of 9,9-bis-dimethyl-4,5-bis(diphenylphosphino)xanthene (62 mg, 0.11 mmol) and tris(dibenzylideneacetone)dipalladium(0) (49 mg, 53 μmol). The reaction mixture was stirred at 80° C. for 20 hours under a flow of nitrogen gas.

Ethyl acetate/water/brine (1/1/1 v/v %, 50 mL) were added to the reaction mixture and stirring was continued for 15 min. After filtration over Decalite® the water layer was separated and extracted with ethyl acetate (2×20 mL). The combined organic layers were subsequently washed with water (40 mL), brine (20 mL), dried over sodium sulphate, filtered and concentrated in vacuo. The crude product was purified by column chromatography on silica (Heptane/Ethyl acetate=1/0 to 0/1 v/v %) to ethyl 2-[4-(4-tert-butoxycarbonylpiperazin-1-yl)-2-methoxy-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (115 mg, 20%).

The thus obtained ethyl ester was subsequently hydrolysed using conditions described for Intermediate 2b. The sodium salt of the corresponding carboxylic acid was subsequently reacted with Intermediate H in an analogous manner as described for Example 8d. After de-protection of the Boc-group, purification was performed using preparative HPLC to afford the title compound (5.2 mg, 28%). Data: LCMS (B) R_(t): 8.140 min; m/z 572.3 (M+H)⁺.

Intermediate K (JDM25/JDM302)

2-Methoxy-4-[1-methyl-4-piperidyloxy]aniline (a) 4-(3-Methoxy-4-nitro-phenoxy)-1-methyl-piperidine

To a solution of 4-fluoro-2-methoxy-1-nitro-benzene (750 mg, 4.38 mmol) in toluene (10 mL) were added 10 mL of a 25% KOH-solution, 4-hydroxy-N-methylpiperidine (1009 mg, 8.76 mmol) and tetra-n-butyl ammonium bromide (282 mg, 0.876 mmol). The mixture was heated at 60° C. o/n. The reaction mixture was then diluted with ethyl acetate and the water layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over sodium sulfate and evaporated. The residue was purified by flash chromatography on silica gel (dichloromethane/methanol=99/1 to 9/1 v/v %) to obtain the title compound. (650 mg, 55.7%)

(b) 2-Methoxy-4-[(1-methyl-4-piperidyl)oxy]aniline (Intermediate K)

10% Pd/C (20 mg) was added as a suspension in ethanol to a solution of 4-(3-methoxy-4-nitro-phenoxy)-1-methyl-piperidine (200 mg, 0.75 mmol) in ethanol (5 mL). The resulting mixture was stirred for 15 min at room temperature. Ammonium formate (473 mg, 7.5 mmol) was added and the reaction mixture was stirred for 1 hour at reflux under nitrogen atmosphere. The reaction mixture was cooled to room temperature and filtered over Decalite®. The filtrate was concentrated in vacuo, after which dichloromethane was added and the organic phase was washed with 5% solution of NaHCO₃. The organic phase was dried over sodium sulfate, filtered and concentrated in vacuo to yield 2-methoxy-4-[(1-methyl-4-piperidyl)oxy]aniline (169.5 mg, 95.6%).

Intermediate L (JDM221J/JDM0222)

3,5-Dimethyl-1H-pyrazol-4-amine

The title compound was prepared in an analogous manner as described for Intermediate Hb, starting from 3,5-dimethyl-4-nitro-1H-pyrazole to give 110 mg 3,5-dimethyl-1H-pyrazol-4-amine (quant.).

Example 16 (JDM323A)

N-(3,5-dimethyl-1H-pyrazol-4-≡(1-2-[2-methoxy-4-[(1-methyl-4-piperidyl)oxy]anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid chloride, using the same sequence of reactions, as described for Intermediate 2, using Intermediate K as starting material. The acid chloride was subsequently reacted with Intermediate L according to procedures described in Example 7. Purification was performed using preparative HPLC to afford the title compound (14.1 mg, 37%). Data: LCMS (B) R_(t): 7.902 min; m/z 543.2 (M+H).

Example 17 (WITJ0529B)

N-(2,6-dimethylphenyl)-2-[2-methoxy-4-[4-(2-methoxyacetyl)piperazin-1-yl]anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding amine (prepared as described for Example 7 starting from Intermediate 1 and Intermediate M) and methoxyacetic acid, using standard HATU-coupling procedures as described in Example 8d. Purification was performed using preparative HPLC to afford the title compound (10 mg, 49%). Data: LCMS (B) R_(t): 12.973 min; m/z 596.3 (M+H)⁺.

Intermediate 3

Ethyl 2-chloropyrimido[4,5-e]indolizine-7-carboxylate (a) Ethyl 2-methoxypyrimido[4,5-e]indolizine-7-carboxylate (JGS362)

DDQ (1.53 g, 6.76 mmol) was added to a stirred solution of ethyl 2-methoxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (1.54 g, 5.63 mmol) in DCM (50 mL). The reaction mixture stirred for 3 days at room temperature. An additional amount of 200 mg DDQ was added and the reaction mixture was stirred for another 7 days at room temperature. The mixture was filtered and concentrated in vacuo to a small volume. The crude product was purified by column chromatography on silica (heptane/ethyl acetate=I/O to 1/1 v/v %) to yield the title compound (750 mg, 50%).

(b) Ethyl 2-hydroxypyrimido[4,5-e]indolizine-7-carboxylate (JGS377)

Sodium iodide (1.24 g, 8.29 mmol) was added to a stirred solution of ethyl 2-methoxy-pyrimido[4,5-e]indolizine-7-carboxylate (750 mg, 2.76 mmol) in acetonitrile (19 mL). A solution of trimethylsilyl chloride (896 mg, 1.05 mL) in acetonitrile (3 mL) was added drop-wise to the reaction mixture. The mixture was stirred at room temperature o/n. Additional sodium iodide (3.33 g) TMS-Cl (2.4 g, 2.8 mL) in acetonitrile (6 mL) were added drop-wise and the reaction was stirred for 3 days at room temperature. The mixture was concentrated under reduced pressure. The residue was suspended in 200 mL DCM/MeOH (4/1) and extracted with a mixture of a saturated solution of sodium thiosulfate (50 mL) and water (100 mL). The water layer was extracted with DCM/MeOH (4/1, 2×150 mL). The combined organic layers were dried over sodium sulfate, filtered and the solvent was removed under reduced pressure to give a solid. The solid was triturated in boiling ethyl acetate (50 mL). After cooling the solid was stirred 1h at room temperature and filtered. The residue was dried at 40° C. under vacuum to give 1.0 g crude ethyl 2-hydroxy-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxylate (quant. yield).

(c) Ethyl 2-chloropyrimido[4,5-e]indolizine-7-carboxylate (Intermediate 3) (JGS380)

N,N-Dimethylaniline (47 mg, 50 μL, 1.50 mmol) was added to a solution of ethyl 2-hydroxypyrimido[4,5-e]indolizine-7-carboxylate (1.0 g, 3.89 mmol) in acetonitrile (30 mL). A solution of phosphorous(V) oxychloride (2.99 g, 1.81 mL, 19.5 mmol) in acetonitrile (4 mL) was added drop-wise to the reaction mixture. The brown/red suspension was heated to 65° C. for 4 hours. After cooling, the mixture was slowly poured in a stirred mixture of 25% aq. ammonia (50 mL) and ice-water (100 mL) keeping the temperature below 10° C. After stirring for another 15 minutes the mixture was extracted with ethyl acetate. The combined organic layers were subsequently washed with water (50 mL), 0.2 N HCl (50 mL), brine (25 mL), dried (Na₂SO₄), filtered and concentrated in vacuo. The crude product was purified by column chromatography on silica (heptane/ethyl acetate=1/0 to 1/1 v/v %) to yield 200 mg of the title compound.

Example 18 (WITJ490B)

N-(2,6-dimethylphenyl)-2-[2-methoxy-4-[(1-methyl-4-piperidyloxy]anilino]pyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid chloride, using the same sequence of reactions as described for Intermediate 2, starting from Intermediate 3 and Intermediate K as starting material. The acid chloride was subsequently reacted with 2,6-dimethylaniline according to procedures described in Example 7. Purification was performed using preparative HPLC to afford the title compound (30 mg, 45%). Data: LCMS (B) R_(t): 12.491 min; m/z 551.3 (M+H)⁺.

Intermediate N (JDM618/JDM626/JDM634)

1-[2-(2-Ethoxyethoxy)ethyl]-3,5-diethyl-pyrazol-4-amine (a) 2-(2-Ethoxyethoxylethyl 4-methylbenzenesulfonate

To a solution of di(ethylene glycol)ethyl ether (4.92 ml, 36.2 mmol) in 15 mL of THF, cooled at 0° C., was added NaOH (2.46 g. 61.5 mmol) dissolved in 15 mL of water with vigorous stirring. To this mixture was added dropwise a solution of tosyl chloride (8.28 g. 43.4 mmol) in 15 mL of THF over 10 min at 0° C. The reaction mixture was then raised to rt and stirred for 1 h under nitrogen. The mixture was then extracted twice with 50 mL of diethyl ether, and the organic layer was washed with 1 M aq NaOH and water and dried over sodium sulfate. Solvent was removed under reduced pressure to yield 2-(2-ethoxyethoxy)ethyl 4-methylbenzenesulfonate as a colorless liquid (10 g. 95.8%).

(b) 1-[2-(2-Ethoxyethoxyl)ethyl]-3,5-dimethyl-4-nitro-pyrazole

To a solution of 3,5-dimethyl-4-nitro-1H-pyrazol (1 g. 7.08 mmol) and cesium carbonate (2.31 g. 7.08 mmol) in DMF (10 mL) was added 2-(2-ethoxyethoxy)ethyl 4-methylbenzenesulfonate (2.04 g. 7.08 mmol). The mixture was heated at 100° C. for 1 h. After cooling to room temperature, the mixture was poured into water/brine and extracted with ethyl acetate (100 mL). The combined organic layer was washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 1.69 g of the title compound (92.8%).

(c) 1-[2-(2-Ethoxyethoxy)ethyl]-3,5-dimethyl-pyrazol-4-amine (Intermediate N)

To a stirred solution of 1-[2-(2-ethoxyethoxy)ethyl]-3,5-dimethyl-4-nitro-pyrazole (1.69 g, 6.57 mmol) in methanol (25 mL) was added a suspension of 10% Pd on charcoal (200 mg) in ethanol (1 mL). The reaction mixture was stirred at room temperature for 15 min under a nitrogen atmosphere. Then, ammonium formate (4.14 g, 65.7 mmol) was added and the reaction mixture was heated to reflux temperature for 15 min. The reaction mixture was cooled, filtered over Decalite® and concentrated in vacuo. The residue was dissolved in methanol and then filtered over an SCX-2 column. After rinsing the column with methanol, the desired product was eluted with an 0.7N ammonia/methanol solution. The resulting eluate was concentrated in vacuo to give the title compound (520 mg, 34.8%).

Example 19 (JDM640A)

N-[1-[2-(2-ethoxyethoxy)ethyl]-3,5-dimethyl-pyrazol-4-yl]-2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate D as starting material. The carboxylic acid was subsequently reacted with Intermediate N in an analogous manner as described for Example 8d. Purification was performed using preparative HPLC to afford the title compound (32.3 mg, 53.9%). Data: LCMS (B) R_(t): 7.432 min; m/z 644.6 (M+H)⁺.

Example 20 (JDM677A)

N-[1-[2-[2-(2-methoxyethoxy)ethoxyethyl]-3,5-dimethyl]-pyrazol-4-yl]-2-[2-methoxy-4-[4-(2-methoxyacetyl)piperazin-1-yl]anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate M as starting material. The carboxylic acid was subsequently reacted with Intermediate C in an analogous manner as described for Example 8d. The corresponding amine was obtained after deprotection of the Cbz-group and methoxyacetic acid was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed using preparative HPLC to afford the title compound (19.0 mg, 63.4%). Data: LCMS (B) R_(t): 8.815 min; m/z 732.7 (M+H)⁺.

Example 21 (JDM711A)

N-[3,5-diethyl-1-[2-(2-methoxyethoxy ethyl]pyrazol-4-yl]-2-[2-methoxy-4-[4-(3-methylazetidine-3-carbonyl)piperazin-1-yl]anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate M as starting material. The carboxylic acid was subsequently reacted with Intermediate I in an analogous manner as described for Example 8d. The corresponding amine was obtained after deprotection of the Cbz-group and 1-(tert-butoxycarbonyl)-3-methylazetidine-3-carboxylic acid was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed, after deprotection of the Boc-group, using preparative HPLC to afford the title compound (16.3 mg, 55%). Data: LCMS (B) R_(t): 8.107 min; m/z 741.8 (M+H)⁺.

Intermediate O (JDM618/JDM625/JDM633)

1-[2-(2-Ethoxyethoxy)ethyl]-3,5-diethyl-pyrazol-4-amine

The title compound was prepared in an analogous manner as described for Intermediate N, starting from 3,5-diethyl-4-nitro-1H-pyrazole (Intermediate Fb) and di(ethylene glycol)ethyl ether to give 550 mg of 1-[2-(2-ethoxyethoxy)ethyl]-3,5-diethyl-pyrazol-4-amine (79.8%.).

Example 22 (JDM713A)

N-[3,5-diethyl-1-[2-(2-methoxyethoxy)ethyl]pyrazol-4-yl]-2-[2-methoxy-4-[4-(3-methylazetidine-3-carbonyl)piperazin-1-yl]anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate M as starting material. The carboxylic acid was subsequently reacted with Intermediate O in an analogous manner as described for Example 8d. The corresponding amine was obtained after deprotection of the Cbz-group and Boc-N-ethyl-glycine was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed, after deprotection of the Boc-group, using preparative HPLC to afford the title compound (15 mg, 53.1%). Data: LCMS (B) R_(t): 8.619 min; m/z 743.8 (M+H)⁺.

Example 23 (JDM697A)

N-[1-[2-(2-ethoxyethoxy)ethyl]-3,5-diethyl-pyrazol-4-yl]-2-[2-methoxy-4-[4-(2-methoxyacetyl)piperazin-1-yl]anilino]-5,6-dihydropyrimido[45-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate M as starting material. The carboxylic acid was subsequently reacted with Intermediate O in an analogous manner as described for Example 8d. The corresponding amine was obtained after deprotection of the Cbz-group and methoxyacetic acid was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed using preparative HPLC to afford the title compound (17.0 mg, 61.4%). Data: LCMS (B) R_(t):10.554 min; m/z 730.7 (M+H)⁺.

Example 24 (JDM636A)

N-[3,5-diethyl-1-[2-[2-(2-methoxyethoxy) ethoxy]ethyl]pyrazol-4-yl]-2-[2-methoxy-4-(4-methylpiperazin-1-yl)anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate D as starting material. The carboxylic acid was subsequently reacted with Intermediate G in an analogous manner as described for Example 8d. Purification was performed using preparative HPLC to afford the title compound (22.5 mg, 34.5%). Data: LCMS (B) R_(t): 7.879 min; m/z 702.7 (M+H).

Example 25 (JDM703A)

N-[3,5-diethyl-1-[2-[2-(2-methoxyethoxy)ethoxy]ethyl]pyrazol-4-yl]-2-[4-[4-[2-(ethylamino)acetyl]piperazin-1-yl]-2-methoxy-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate M as starting material. The carboxylic acid was subsequently reacted with Intermediate G in an analogous manner as described for Example 8d. The corresponding amine was obtained after deprotection of the Cbz-group and Boc-N-ethyl-glycine was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed, after deprotection of the Boc-group, using preparative HPLC to afford the title compound (18.4 mg, 59.4%). Data: LCMS (B) R_(t): 8.194 min; m/z 773.8 (M+H)⁺.

Example 26 (JDM709A)

2-[4-[4-[(2R)-azetidine-2-carbonyl]piperazin-1-yl]-2-methoxy-anilino]-N-[3,5-diethyl-1-[2-(2-methoxyethoxy)ethyl]pyrazol-4-yl]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid, using the same sequence of reactions, as described for Intermediate 2b, using Intermediate M as starting material. The carboxylic acid was subsequently reacted with Intermediate I in an analogous manner as described for Example 8d. The corresponding amine was obtained after deprotection of the Cbz-group and (R)—N-Boc-azetidine-2-carboxylic acid was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed, after deprotection of the Boc-group, using preparative HPLC to afford the title compound (16.8 mg, 57.7%). Data: LCMS (B) R_(t): 8.017 min; m/z 727.9 (M+H)⁺.

Example 27 (JDM666A)

N-(2,6-dimethylphenyl-2-[4-[4-[2-ethylamino)acetyl]piperazin-1-yl]-2-methoxy-anilino]-5,6-dihydropyrimido[4,5-e]indolizine-7-carboxamide

This compound was prepared from its corresponding acid chloride, using the same sequence of reactions, as described for Intermediate 2, using Intermediate M as starting material. The acid chloride was subsequently reacted with 2,6-dimethylaniline in an analogous manner as described for Example 7. The corresponding amine was obtained after deprotection of the Cbz-group and Boc-N-ethyl-glycine was introduced, using standard HATU-coupling procedures as described in Example 8d. Purification was performed, after deprotection of the Boc-group, using preparative HPLC to afford the title compound (1 mg, 13.2%). Data: LCMS (B) R_(t): 9.388 min; m/z 609.6 (M+H)⁺.

Example 28 (JGS0715B)

N-cyclopropyl-4-[6-(2,3-difluoro-4-methoxy-phenoxy)-8-(3,3,3-trifluoropropylamino)imidazo[1,2-b]pyridazin-3-yl]-2-methyl-benzamide

This compound was prepared as described in WO 2014/131739 A1. Purification was performed using preparative HPLC to afford the title compound (30 mg). Data: LCMS (B) R_(t): 14.958 min; m/z 562.5 (M+H)⁺.

Example 29 (JDM943D)

(2R)-2-(4-fluorphenyl)-N-[4-[2-(2-methoxy-4-methylsulfonyl-anilino)-[1,2,4]triazolo-[1,5-a]pyridin-6-yl]phenyl]propanamide

This compound was prepared as described in WO 2014/009219 A1. Purification was performed using preparative HPLC to afford the title compound (107.1 mg). Data: LCMS (B) R_(t): 13.703 min; m/z 558.0 (M−H)⁻.

Example 30 (JDM969A)

1-[4-[[4-(2-Isopropylsulfonylanilino)-1H-pyrrolo[2,3-b]pyridin-6-yl]amino]-3-methoxy-phenyl]piperidin-4-ol (Mps1-IN-1)

This compound was purchased from Tocris.

Example 31 (JDM969B)

4-[[4-Amino-6-(tert-butylamino)-5-cyano-2-pyridyl]amino]benzamide (TC Mps1 12)

This compound was purchased from Tocris.

TTK Enzyme Assay

The inhibitory activity of compounds on biochemically purified full-length TTK (Life Technologies, Madison, Wis., U.S.A.) was determined in the IMAP® assay (Molecular Devices, Sunnyvale, Calif., U.S.A.). Compounds were dissolved in 100% dimethylsulfoxide (DMSO). At the day of the experiment, the compound stock was diluted in 3.16 fold steps in 100% DMSO, to obtain a 10-point dilution series, followed by further dilution in IMAP reaction buffer, which consists of 10 mM Tris-HCl, pH 7.5, 10 mM MgCl₂, 0.01% Tween-20, 0.1% NaN₃ and 1 mM freshly prepared dithiothreitol. Compound solution was mixed with an equal volume of full-length TTK enzyme in IMAP reaction buffer. After pre-incubation of 1 hour in the dark at room temperature, fluorescein-labeled MBP-derived substrate peptide (Molecular Devices) was added and ATP to start the reaction. Final enzyme concentration was 3.9 nM, final substrate concentration 50 nM, and final ATP concentration was 5 μM. The reaction was allowed to proceed for 2 hours at room temperature in the dark. The reaction was stopped by quenching with IMAP progressive binding solution according to the protocol of the manufacturer (Molecular Devices). Fluorescein polarization was measured on an Envision multimode reader (Perkin Elmer, Waltham, Mass., USA). Dose-response curves were fitted to a four-parameter logarithmic equation in XLfit™ 5 (ID Business Solutions, Ltd., Guildford, U.K.). Table 3 show the half-maximum inhibitory potency of a number of TTK inhibitors from different chemical classes in an enzyme assay for TTK.

TABLE 3 Activity of small molecule TTK inhibitors in TTK enzyme assay. Example nr. IC₅₀ (nM) Example 1 2.6 Example 2 4.1 Example 3 0.63 Example 4 0.49 Example 5 0.65 Example 6 0.6 Example 7 0.7 Example 8 0.6 Example 9 0.73 Example 10 0.93 Example 11 0.6 Example 12 0.97 Example 13 0.43 Example 14 0.98 Example 15 1.1 Example 16 1.0 Example 17 1.0 Example 18 1.4 Example 19 1.14 Example 20 0.62 Example 21 0.96 Example 22 0.71 Example 23 0.41 Example 24 0.91 Example 25 0.43 Example 26 0.66 Example 27 0.41 Example 28 0.79 Example 29 2.55 Example 30 37.5 Example 31 7.0

In order to identify genomic biomarkers that correlate with the sensitivity of cancer cells to the TTK inhibitors, the compounds were tested in proliferation assays with sixty-six different, genetically well-characterized cancer cell lines.

Statistical analysis of the anti-proliferative activity of the inhibitors with the presence of specific cancer gene mutations in the cell lines revealed that TTK inhibitors preferentially kill cells that harbor mutation in the CTNNB1 gene known to be involved in regulation of the stability of the CTNNB1-encoded protein β-catenin.

FIGS. 2A-2G show the volcano plot of the Anova analysis of Examples 5, 8, 9, 12, 13 and 17. To verify if a TTK inhibitor was significantly more potent in cell lines expressing mutant CTNNB1 in comparison to cell lines not harboring mutation in CTNNB1, a one-sided Student's t-test was carried out. Table 4 shows the difference in sensitivity (ΔpIC₅₀) of a number of representative TTK inhibitors from different chemical classes. A negative ΔpIC₅₀ value indicates that CTNNB1 mutant cell lines are more sensitive to the inhibitor than cell lines not harboring mutations in the regulatory domain of the CTNNB1 gene (Table 2). A p value <0.05 indicates that the difference is significant.

TABLE 4 Difference in sensitivity of CTNNB1-mutant and non-mutant cell lines for TTK inhibitors pIC50 average¹ significance Example nr. Wild type³ Mutant³ Δ pIC50 p-value² Example 1 6.15 6.78 −0.63 5.0E−03 Example 2 5.73 5.98 −0.25 3.6E−02 Example 3 5.68 6.01 −0.33 2.4E−02 Example 4 7.21 7.64 −0.43 3.3E−02 Example 5 7.06 7.60 −0.54 1.2E−02 Example 6 6.93 7.64 −0.71 8.8E−03 Example 7 7.47 7.92 −0.45 2.6E−02 Example 8 7.38 7.96 −0.57 1.3E−02 Example 9 7.50 8.18 −0.68 1.9E−02 Example 10 6.86 7.41 −0.55 1.4E−02 Example 11 6.99 7.48 −0.49 2.7E−02 Example 12 6.96 7.65 −0.69 6.5E−03 Example 13 7.82 8.60 −0.79 7.1E−03 Example 14 7.47 8.01 −0.54 1.8E−02 Example 15 6.60 7.28 −0.69 3.9E−03 Example 16 6.46 7.22 −0.76 4.6E−03 Example 17 7.72 8.33 −0.61 1.7E−02 Example 18 7.53 8.13 −0.60 2.9E−02 Example 19 7.20 7.72 −0.53 9.3E−03 Example 20 7.28 7.90 −0.2 8.7E−03 Example 21 7.19 7.98 −0.79 1.2E−02 Example 22 7.70 8.34 −0.65 9.1E−03 Example 23 7.97 8.55 −0.59 2.0E−02 Example 24 7.59 8.09 −0.50 2.5E−02 Example 25 7.62 8.37 −0.75 3.2E−03 Example 26 7.28 7.96 −0.68 9.9E−03 Example 27 7.60 8.17 −0.57 1.9E−02 Example 28 7.00 7.47 −0.47 1.1E−02 Example 29 6.40 6.72 −0.31 1.8E−02 Example 30 5.17 5.39 −0.23 1.0E−01 Example 31 6.02 6.36 −0.34 2.8E−02 ¹defined as-¹⁰log IC₅₀ (in M) ²one-side student T-test, heteroscedastic ³referring to CTNNB1 gene

In order to verify that the presence of a mutated CTNNB1 gene copy is sufficient to confer increased sensitivity to TTK inhibitors, proliferation assays were carried out with parental HCT116 cells (S45del/+) and an isogenic derivative lacking mutated CTNNB1 (−/+). Table 5 summarizes the difference in sensitivity of a number of representative TTK inhibitors from different chemical classes in the isogenic cell line in comparison to parental HCT116 cells. A negative ΔpIC₅₀ or a negative Δefficacy indicates that HCT116 parental cells, expressing mutant CTNNB1 (S45del/+) are more sensitive to the inhibitor than the isogenic derivative, in which the mutated CTNNB1 gene has been removed (−/+). Thus, inhibitors with a negative ΔpIC50 or a negative Δefficacy better inhibit the cell line where mutant CTNNB1 signaling is present.

TABLE 5 Difference in sensitivity for TTK inhibitors in HCT116 cells expressing either a mutated copy of the CTNNB1 gene or not. ΔpIC₅₀ Δefficacy Example 5 −0.17 −26 Example 8 −0.29 −11 Example 12 −0.14 −18 Example 13 −0.01 −27 Example 17 −0.12 −16 Example 20 −0.20 −34 

The invention claimed is:
 1. A method for treating a tumor in a human individual or an animal that is susceptible to treatment with a TTK inhibitor, the method comprising: determining that the tumor is susceptible to treatment with the TTK inhibitor when the presence of a mutated CTNNB1 gene having a mutation located in exon 3 has been detected in a tumor sample from the human individual or animal; and treating, with the TTK inhibitor, the human individual or animal whose tumor is determined to be susceptible to treatment with the TTK inhibitor, wherein the TTK inhibitor is a chemical compound belonging to the class of compounds according to Formula I:

wherein: R¹ is selected from the group consisting of:

R¹¹ is H, halogen, (1-2C)alkyl, (2-3C)alkenyl, (2-3C)alkynyl, (1-2C)alkoxy or OC₂H₃, all alkyl and alkoxy groups optionally being substituted with one or more halogen; R¹² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R¹³ is R¹³¹CH₂, R¹³²O, R¹³³R¹³⁴N, R¹³⁵C(O), R¹³⁶S, R¹³⁶S(O), R¹³⁶S(O)(NH), R¹³⁷SO₂, (2-7C)heterocycloalkyl, or (1-5C)heteroaryl each heterocycloalkyl or heteroaryl optionally being substituted with (1-2C)alkyl, fluoro, hydroxyl, oxo, (1-2C)alkoxy, (1-6C)alkylcarbonyl, (1-6C)alkylsulfonyl, (1-5C)alkoxycarbonyl, (1-6C)alkylaminocarbonyl, (3-6C)cycloalkylcarbonyl, (2-7C)heterocycloalkylcarbonyl or di[(1-2C)alkyl]amino, each alkylcarbonyl, alkylsulfonyl, alkoxycarbonyl, alkylaminocarbonyl, cycloalkylcarbonyl or heterocycloalkylcarbonyl optionally being substituted with (1-2C)alkyl, fluoro, hydroxyl, cyano, oxo or (1-2C)alkoxy; R¹³¹ is (1-6C)alkylcarbonylamino, (3-6C)cycloalkylcarbonylamino or (2-7C)heterocycloalkylcarbonylamino each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; R¹³² is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl, (6-10C)aryl or (1-5C)heteroraryl each optionally substituted with one or more groups selected from (1-2C)alkyl, halogen, hydroxyl, (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; R¹³³ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl (1-6C)alkylcarbonyl, (1-5C)alkoxycarbonyl, (3-6C)cycloalkylcarbonyl or (2-7C)heterocycloalkylcarbonyl, each optionally substituted with one or more groups selected from (1-2C)alkyl, halogen, hydroxyl or (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; R¹³⁴ is hydrogen or (1-2C)alkyl; R¹³⁵ is (2-7C)heterocycloalkyl, (1-6C)alkylamino, di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino or (3-6C)cycloalkylamino each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl, (1-2C)alkoxy, di[(1-2C)alkyl]amino, (2-7C)heterocycloalkyl, oxo, cyano or amino; R¹³⁶ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; R¹³⁷ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl, (1-6C)alkylamino, di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino or (3-6C)cycloalkylamino, each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; R¹⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; and R¹⁵ is H, halogen; in the above Formula I, R² is selected from the group consisting of:

R²¹ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl, (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; R²² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R²³ is H, halogen, (1-2C)alkyl, (1-2C)alkoxy, cyano or hydroxy; R²⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R²⁵ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl, (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; R²⁶ is H, (1-6C)alkyl, (3-6C)cycloalkyl, (2-5C)heterocycloalkyl, (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl, wherein n represents an integer of 1,2,3 or 4, all alkyl, heterocycloalkyl and (1-2C)alkoxy[(2-4C)alkoxy]_(n), (1-6C)alkyl groups optionally substituted with one or more groups selected from (1-2C)alkyl, (1-2C)alkoxy, hydroxyl, oxo, amino, (3-6C)cycloalkyl, di[(1-2C)alkyl]amino or (2-5C)heterocycloalkyl; and wherein in the above Formula I only one of R²¹ and R²⁵ in R² can be H.
 2. The method according to claim 1, wherein the mutation is a missense mutation or a deletion of the serine residue corresponding to codon 33 of CTNNB1.
 3. The method according to claim 1, wherein the mutation is a missense mutation or a deletion of the threonine residue corresponding to codon 41 of CTNNB1.
 4. The method according to claim 1, wherein the mutation is a missense mutation or a deletion of the serine residue corresponding to codon 45 of CTNNB1.
 5. The method according to claim 1, wherein the presence of the mutated CTNNB1 gene has been detected in tumor DNA in the tumor sample.
 6. The method according to claim 1, wherein the presence of the mutated CTNNB1 gene has been detected in tumor mRNA in the tumor sample.
 7. The method according to claim 1, wherein the presence of the mutated CTNNB1 gene has been detected by analyzing the amino acid sequence or phosphorylation of β-catenin in the tumor sample.
 8. The method according to claim 1, wherein the tumor sample is taken from a tumor biopsy.
 9. The method according to claim 1, wherein the tumor sample is taken from circulating tumor cells.
 10. The method according to claim 5, wherein the tumor DNA is taken from a tumor biopsy.
 11. The method according to claim 5, wherein the tumor DNA is derived from circulating tumor DNA.
 12. A method for treating a tumor in a human individual or an animal, the method comprising: detecting whether a mutated CTNNB1 gene having a mutation located in exon 3 is present in a tumor sample from the human individual or animal; diagnosing the human individual or animal as being susceptible to treatment with a TTK inhibitor when the presence of the mutated CTNNB1 gene in the tumor sample is detected; and treating the diagnosed human individual or animal with the TTK inhibitor, wherein the TTK inhibitor is a chemical compound belonging to the class of compounds according to Formula I:

wherein: R¹ is selected from the group consisting of:

R¹¹ is H, halogen, (1-2C)alkyl, (2-3C)alkenyl, (2-3C)alkynyl, (1-2C)alkoxy or OC₂H₃, all alkyl and alkoxy groups optionally being substituted with one or more halogen; R¹² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R¹³ is R¹³¹CH₂, R¹³²O, R¹³³R¹³⁴N, R¹³⁵C(O), R¹³⁶S, R¹³⁶S(O), R¹³⁶S(O)(NH), R¹³⁷SO₂, (2-7C)heterocycloalkyl, or (1-5C)heteroaryl each heterocycloalkyl or heteroaryl optionally being substituted with (1-2C)alkyl, fluoro, hydroxyl, oxo, (1-2C)alkoxy, (1-6C)alkylcarbonyl, (1-6C)alkylsulfonyl, (1-5C)alkoxycarbonyl, (1-6C)alkylaminocarbonyl, (3-6C)cycloalkylcarbonyl, (2-7C)heterocycloalkylcarbonyl or di[(1-2C)alkyl]amino, each alkylcarbonyl, alkylsulfonyl, alkoxycarbonyl, alkylaminocarbonyl, cycloalkylcarbonyl or heterocycloalkylcarbonyl optionally being substituted with (1-2C)alkyl, fluoro, hydroxyl, cyano, oxo or (1-2C)alkoxy; R¹³¹ is (1-6C)alkylcarbonylamino, (3-6C)cycloalkylcarbonylamino or (2-7C)heterocycloalkylcarbonylamino each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; R¹³² is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl, (6-10C)aryl or (1-5C)heteroraryl each optionally substituted with one or more groups selected from (1-2C)alkyl, halogen, hydroxyl, (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; R¹³³ is (1-6C)alkyl,(3-6C)cycloalkyl, (2-7C)heterocycloalkyl (1-6C)alkylcarbonyl, (1-5C)alkoxycarbonyl, (3-6C)cycloalkylcarbonyl or (2-7C)heterocycloalkylcarbonyl, each optionally substituted with one or more groups selected from (1-2C)alkyl, halogen, hydroxyl or (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; R¹³⁴ is hydrogen or (1-2C)alkyl; R¹³⁵ is (2-7C)heterocycloalkyl, (1-6C)alkylamino, di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino or (3-6C)cycloalkylamino each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl, (1-2C)alkoxy, di[(1-2C)alkyl]amino, (2-7C)heterocycloalkyl, oxo, cyano or amino; R¹³⁶ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; R¹³⁷ is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl, (1-6C)alkylamino, di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino or (3-6C)cycloalkylamino, each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl or (1-2C)alkoxy; R¹⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; and R¹⁵ is H, halogen; in the above Formula I, R² is selected from the group consisting of:

R²¹ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl, (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; R²² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R²³ is H, halogen, (1-2C)alkyl, (1-2C)alkoxy, cyano or hydroxy; R²⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R²⁵ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl, (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; R²⁶ is H, (1-6C)alkyl, (3-6C)cycloalkyl, (2-5C)heterocycloalkyl, (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl, wherein n represents an integer of 1,2,3 or 4, all alkyl, heterocycloalkyl and (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl groups optionally substituted with one or more groups selected from (1-2C)alkyl, (1-2C)alkoxy, hydroxyl, oxo, amino, (3-6C)cycloalkyl, di[(1-2C)alkyl]amino or (2-5C)heterocycloalkyl; and wherein in the above Formula I only one of R²¹ and R²⁵ in R² can be H.
 13. The method according to claim 1, wherein said mutation results in a substitution of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein, or wherein said mutation is a deletion of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein.
 14. The method according to claim 1, wherein in Formula I: R¹ is

R¹¹ is H, halogen, (1-2C)alkyl, (2-3C)alkenyl, (2-3C)alkynyl, (1-2C)alkoxy or OC₂H₃, all alkyl and alkoxy groups optionally being substituted with one or more halogen; R¹² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R¹³ is R¹³²O, R¹³⁵C(O), (2-7C)heterocycloalkyl, or (1-5C)heteroaryl each heterocycloalkyl or heteroaryl optionally being substituted with (1-2C)alkyl, fluoro, hydroxyl, oxo, (1-2C)alkoxy, (1-6C)alkylcarbonyl, (1-6C)alkylsulfonyl, (1-5C)alkoxycarbonyl, (1-6C)alkylaminocarbonyl, (3-6C)cycloalkylcarbonyl, (2-7C)heterocycloalkylcarbonyl or di[(1-2C)alkyl]amino, each alkylcarbonyl, alkylsulfonyl, alkoxycarbonyl, alkylaminocarbonyl, cycloalkylcarbonyl or heterocycloalkylcarbonyl optionally being substituted with (1-2C)alkyl, fluoro, hydroxyl, cyano, oxo or (1-2C)alkoxy; R¹³² is (1-6C)alkyl, (3-6C)cycloalkyl, (2-7C)heterocycloalkyl, (6-10C)aryl or (1-5C)heteroraryl each optionally substituted with one or more groups selected from (1-2C)alkyl, halogen, hydroxyl, (1-2C)alkoxy, di[(1-2C)alkyl]amino or (2-7C)heterocycloalkyl; R¹³⁵ is (2-7C)heterocycloalkyl, (1-6C)alkylamino, di[(1-6C)alkyl]amino, (2-7C)heterocycloalkylamino or (3-6C)cycloalkylamino each optionally substituted with one or more groups selected from (1-2C)alkyl, fluoro, hydroxyl, (1-2C)alkoxy, di[(1-2C)alkyl]amino, (2-7C)heterocycloalkyl, oxo, cyano or amino; R¹⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; and R¹⁵ is H, halogen; R² is selected from the group consisting of:

R²¹ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl, (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; R²² is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R²³ is H, halogen, (1-2C)alkyl, (1-2C)alkoxy, cyano or hydroxy; R²⁴ is H, halogen, (1-2C)alkyl or (1-2C)alkoxy; R²⁵ is H, halogen, (1-3C)alkyl, (1-2C)alkoxy, hydroxy(1-2C)alkyl, (3-4C)cycloalkyl, (2-3C)alkenyl or cyano; R²⁶ is H, (1-6C)alkyl, (3-6C)cycloalkyl, (2-5C)heterocycloalkyl, (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl, wherein n represents an integer of 1,2,3 or 4, all alkyl, heterocycloalkyl and (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl groups optionally substituted with one or more groups selected from (1-2C)alkyl, (1-2C)alkoxy, hydroxyl, oxo, amino, (3-6C)cycloalkyl, di[(1-2C)alkyl]amino or (2-5C)heterocycloalkyl; and wherein in the above Formula I only one of R²¹ and R²⁵ in R² can be H.
 15. The method according to claim 1, wherein in Formula I: R¹ is

R¹¹ is (1-2C)alkoxy, the alkoxy optionally being substituted with one or more halogen; R¹² is H; R¹³ is R¹³²O, R¹³⁵C(O), (2-7C)heterocycloalkyl, or (1-5C)heteroaryl each heterocycloalkyl or heteroaryl optionally being substituted with (1-2C)alkyl, (1-6C)alkylcarbonyl, or (2-7C)heterocycloalkylcarbonyl, each alkylcarbonyl or heterocycloalkylcarbonyl optionally being substituted with (1-2C)alkyl or (1-2C)alkoxy; R¹³² is (2-7C)heterocycloalkyl, optionally substituted with one or more groups selected from (1-2C)alkyl; R¹³⁵ is (2-7C)heterocycloalkyl or (2-7C)heterocycloalkylamino, each optionally substituted with one or more groups selected from (1-2C)alkyl; R¹⁴ is H; and R¹⁵ is H; R² is selected from the group consisting of:

R²¹ is (1-3C)alkyl; R²² is H; R²³ is H; R²⁴ is H; R²⁵ is (1-3C)alkyl; R²⁶ is H, (1-6C)alkyl, or (1-2C)alkoxy[(2-4C)alkoxy]_(n)(1-6C)alkyl, wherein n represents an integer of 1, 2, 3 or
 4. 16. The method according to claim 13, wherein said mutation results in a substitution of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein at a position selected from S33, S37, S45 and T41, or wherein said mutation is a deletion of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein at a position selected from S33, S37, S45 and T41.
 17. The method according to claim 15, wherein said mutation results in a substitution of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein, or wherein said mutation is a deletion of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein.
 18. The method according to claim 17, wherein said mutation results in a substitution of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein at a position selected from S33, S37, S45 and T41, or wherein said mutation is a deletion of one or more serine or threonine residues in the corresponding CTNNB1-encoded protein at a position selected from S33, S37, S45 and T41.
 19. The method according to claim 15, wherein the mutation is a missense mutation or a deletion of the serine residue corresponding to codon 33 of CTNNB1.
 20. The method according to claim 15, wherein the mutation is a missense mutation or a deletion of the threonine residue corresponding to codon 41 of CTNNB1.
 21. The method according to claim 15, wherein the mutation is a missense mutation or a deletion of the serine residue corresponding to codon 45 of CTNNB1. 